Just fyi: You can use the inf Python artifact to disable limits that grow. You can use 0 to disable limits that converge toward zero. It should have been documented but it has been omitted for no apparent reason. 
Actually, there is no image count that makes a sequence get stuck or fully processed. In fact, there are sequences with over 15k images that have been processed just fine. On the other hand, I have had sequences with as few as 137 and 287 images stuck in “Map Data Processing”. This is a systemic issue. Sadly, the issue has been consistently sidelined and down played for years by Mapillary. 
At least, this is my impression. The official policy animates you to upload as many images per sequence as you like, which makes sense. Technically, it is generally possible to upload as many images per sequence as you like, no image gets lost, and you can view every image after upload but in practice there is no guarantee that any of your sequences, no matter how many or few images they may have, are going to get fully processed.