It also seem that Crowdin exports Qt TS files using the first format (at least from what I’ve seen using the Github integration), even when provided the second format as an input, causing big diffs and possibly issues when re-importing the exported files.
I guess plural form detection could be based on the numerus="yes" attribute on the <message> object, rather than the presence of a <numerusform> inside <translation> (at least that’s what it seem to be doing).
As far as I understand you are using GitHub to manage the files. Could you please also share with us the screenshot of how this sting is displayed directly in the Editor?
Sure, although this can also be reproduced by just importing the file as a new source translation. Here’s how the file with only numerus="yes" looks like (translating to French):
Indeed, in order for the plurals to be correctly recognized in the Qt TS format, it is necessary to add <numerusform/> attribute to the file. You are welcome to read more details on this file format in our Store.