Status "Internal server error." when translating .srt file with single space wrapped in html <i> </i>

[polarbearing]

When translating .srt files with some html markup for italics, I get status "Internal server error." while the file upload still gives HTTP code was 200.

The upload request returns a document_id and document_key, however when checking the status of the translation, it responds:
{"document_id":"4A7977F8FCF75CCD30FF8350E4F2E6A4","status":"error","error_message":"Internal server error.","message":"Internal server error."}

The offending construct were single spaces wrapped in html like previous word<i> </i>next word

Test .srt file:

1
00:07:04,880 --> 00:07:08,320
There is some pointless html tagging around a single space<i> </i>here.

2
00:07:15,520 --> 00:07:16,720
This <i>Example</i> works fine.

When I remove the tags in statement 1 it works fine:
{"document_id":"BD19DE252546E8FE610A3E74A285D2AA","status":"done","billed_characters":92}

1
00:07:04,880 --> 00:07:08,320
Hier gibt es einige sinnlose HTML-Tags um 
ein einzelnes Leerzeichen herum. 

2
00:07:15,520 --> 00:07:16,720
Dieses <i>Beispiel </i> funktioniert gut