No, they didn't. What happened relatively recently was the DST cross sign expired; but any device should, by that point, have received the ISRG root, or you ha

No, they didn't. What happened relatively recently was the DST cross sign expired; but any device should, by that point, have received the ISRG root, or you haven't gotten security updates in the last 7 years. Additionally, there were/are problems with some TLS libraries (e.g., GnuTLS) that have bugs in path building. (Fixes have been made, since LE not working is pretty obvious.) They'll build a path to the expired DST cert, and then conclude (incorrectly) that no other valid path can exist. (When in fact, there is, to LE's own root.) (Additionally, I've also seen vendors corrupt the ca-certificates directory, and then OpenSSL fails to do path building. This is sort of a pathological case, and probably not your phone's issue.)