Interesting, saw reCAPTCHA infinite loop for the first time in a long time just yesterday, on Firefox, and it was when I tried to access an article on PMC. Disabling uBlock and Enhanced Tracking Protection did not help. It looked like several automatic reloads, then one real reCAPTCHA showed, and infinite reload loop after I solved it.

Does not reproduce today though, and I never had issues with PMC/NIH before that.