Formatter adding new lines

[rkent-sgs]

I can't work out why the formatter is adding blank lines when I format my file:

Before

<div class="flexibleblocks-block">
	<section class="table-block">
		<!--mixcontent-->
		<div class="container">
			<div class="row">
				<div class="col-lg-10 offset-lg-1">
					<?php include($_SERVER["DOCUMENT_ROOT"] . '/structure/flexcontent/table.php'); ?>
				</div>
			</div>
		</div>
		<!--mixcontent-->
	</section>
</div>
<!-- flexible block -->

After

<div class="flexibleblocks-block">
	<section
		class="table-block">
		<!--mixcontent-->
		<div class="container">
			<div class="row">
				<div class="col-lg-10 offset-lg-1">
					<?php include($_SERVER["DOCUMENT_ROOT"] . '/structure/flexcontent/table.php'); ?>
				</div>
			</div>
		</div>
		<!--mixcontent-->
	</section>
</div>
<!-- flexible block -->

The section class is moved to a new line and the cursor moved there, but the line isn't too long nor are other tags broken up like this. Is this a bug?

[rkent-sgs]

I've noticed this doesn't happen if I remove the <!--mixcontent--> line

[rkent-sgs]

Actually, this seems to happen a lot with comments