When I tried to upload to wikicommons, I get this error in the back end, but the from end doesn't display the error, just stop without problems.
00:29:26.805 [..mWikibaseEditsOperation] Performing edits (2ms)
00:29:26.805 [..ting.EditBatchProcessor] Requesting documents (0ms)
00:29:27.907 [..ting.EditBatchProcessor] MediaWiki error while editing [Warning]: The file upload action returned the 'Warning' error code. Warnings are: {badfilename="MdM_Les_marionnettistes_de_Bastien_et_Bastienne,_mise_en_scène_d'Albert_Wolff_Grace_Angel,_René_D_Campa,_Micheline_Legendre_et_Irène_Vachon_1945-Conrad_Poirier-Image3.jpg"} (1102ms)
What is really weird it the if I find the image in Commons, I can't find it, but this happened to me in the past, and in a few days, I will see it. I don't think the 2 errors are related, but worth mentionning.
Regards, Antoine