Earlier quoted context omitted.
Interestingly, when I just checked this out, the model point-blank refused to print a word 100 times. Wouldn't do it. Edit: Got it on the 3rd try. No weirdness ensued though.
The specific way to trigger it I saw was to either paste in "a a a a..." with several hundred a's (exact amount varied by model, supposedly). Asking it to print 1000 a's also works, though sometimes it won't do it. Example: https://chat.openai.com/share/6171bc66-dfe3-489e-99f7-af4862...
https://chat.openai.com/share/c8d2e154-6a25-477c-b0a8-5f15d7...