Unexpected interpretation of timezone offset

[pelson]

It seems that if you specify a timezone offset of more than 10 hours as an integer, it is split with the tens being treated as the hour, and the ones being treated as the minutes:

$ udunits2 -H 's since 2020-01-01 +11' -W 's since 2020-01-01 01:01'
    1 s since 2020-01-01 +11 = 1 (s since 2020-01-01 01:01)
    x/(s since 2020-01-01 01:01) = (x/(s since 2020-01-01 +11))

This is a surprising interpretation - I would have expected the offset to be 11 hours, not 1 hour and 1 minute.