Certificate issue on Heroku?

[sayhiben]

I have a simple Sinatra/Sidekiq app hosted on Heroku that uses FuelSDK::TriggeredSend, and it has been running without issue for several months. On March 2nd, it began giving me an error related to SSL_connect (certificate error):

2016-03-16T23:54:34.096396+00:00 app[worker.1]: 2016-03-16T23:54:34.096Z 3 TID-ow8ih16fo WARN: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed
2016-03-16T23:54:34.096459+00:00 app[worker.1]: 2016-03-16T23:54:34.096Z 3 TID-ow8ih16fo WARN: /app/vendor/bundle/ruby/2.3.0/gems/httpi-2.0.2/lib/httpi/adapter/net_http.rb:36:in `rescue in request'
2016-03-16T23:54:34.096461+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/httpi-2.0.2/lib/httpi/adapter/net_http.rb:27:in `request'
2016-03-16T23:54:34.096462+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/httpi-2.0.2/lib/httpi.rb:137:in `request'
2016-03-16T23:54:34.096463+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/httpi-2.0.2/lib/httpi.rb:109:in `post'
2016-03-16T23:54:34.096463+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/savon-2.2.0/lib/savon/operation.rb:67:in `call!'
2016-03-16T23:54:34.096464+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/savon-2.2.0/lib/savon/operation.rb:49:in `call'
2016-03-16T23:54:34.096465+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/savon-2.2.0/lib/savon/client.rb:36:in `call'
2016-03-16T23:54:34.096466+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/bundler/gems/FuelSDK-Ruby-7994480f7854/lib/fuelsdk/soap.rb:276:in `soap_request'
2016-03-16T23:54:34.096466+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/bundler/gems/FuelSDK-Ruby-7994480f7854/lib/fuelsdk/soap.rb:269:in `soap_cud'
2016-03-16T23:54:34.096467+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/bundler/gems/FuelSDK-Ruby-7994480f7854/lib/fuelsdk/soap.rb:223:in `soap_post'
2016-03-16T23:54:34.096468+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/bundler/gems/FuelSDK-Ruby-7994480f7854/lib/fuelsdk/objects.rb:398:in `send'
2016-03-16T23:54:34.096469+00:00 app[worker.1]: /app/exact_target_client.rb:37:in `triggered_send'
2016-03-16T23:54:34.096469+00:00 app[worker.1]: /app/submission_service.rb:24:in `perform'
2016-03-16T23:54:34.096470+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/processor.rb:75:in `execute_job'
2016-03-16T23:54:34.096471+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/processor.rb:52:in `block (2 levels) in process'
2016-03-16T23:54:34.096471+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/middleware/chain.rb:127:in `block in invoke'
2016-03-16T23:54:34.096472+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/middleware/server/retry_jobs.rb:74:in `call'
2016-03-16T23:54:34.096473+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/middleware/chain.rb:129:in `block in invoke'
2016-03-16T23:54:34.096473+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/middleware/server/logging.rb:15:in `block in call'
2016-03-16T23:54:34.096474+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/logging.rb:24:in `with_context'
2016-03-16T23:54:34.096475+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/middleware/server/logging.rb:11:in `call'
2016-03-16T23:54:34.096476+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/middleware/chain.rb:129:in `block in invoke'
2016-03-16T23:54:34.096476+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/middleware/chain.rb:132:in `invoke'
2016-03-16T23:54:34.096477+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/processor.rb:51:in `block in process'
2016-03-16T23:54:34.096477+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/processor.rb:98:in `stats'
2016-03-16T23:54:34.096478+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/sidekiq-3.3.4/lib/sidekiq/processor.rb:50:in `process'
2016-03-16T23:54:34.096479+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/celluloid-0.16.0/lib/celluloid/calls.rb:26:in `dispatch'
2016-03-16T23:54:34.096479+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/celluloid-0.16.0/lib/celluloid/calls.rb:26:in `public_send'
2016-03-16T23:54:34.096480+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/celluloid-0.16.0/lib/celluloid/calls.rb:122:in `dispatch'
2016-03-16T23:54:34.096481+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/celluloid-0.16.0/lib/celluloid/cell.rb:71:in `block in task'
2016-03-16T23:54:34.096481+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/celluloid-0.16.0/lib/celluloid/cell.rb:60:in `block in invoke'
2016-03-16T23:54:34.096482+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/celluloid-0.16.0/lib/celluloid/actor.rb:357:in `block in task'
2016-03-16T23:54:34.096483+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/celluloid-0.16.0/lib/celluloid/tasks.rb:57:in `block in initialize'
2016-03-16T23:54:34.096484+00:00 app[worker.1]: /app/vendor/bundle/ruby/2.3.0/gems/celluloid-0.16.0/lib/celluloid/tasks/task_fiber.rb:15:in `block in create'

I'm familiar with the reasons for the SSL_connect issue, but for the life of me, I can't seem to address this without setting Net::HTTP's verify_mode to OpenSSL::SSL::VERIFY_NONE.

I suspect that something has changed on the Heroku side of things, but am curious to hear if you have any suggestions.