The FSF does not consider GPLv2 to be Apache 2.0 compatible, telegram-FOSS is GPLv2, and Android/AOSP is Apache v2.
Additionally, their own codebase contains a bunch of Apache v2 licensed stuff, like exoplayer2, recyclerview, libtgvoip, fastdateparser, ABSL, etc.
They do not appear to be even giving attribution as required (or at least i can't find it)
They are in no worse a position than they were yesterday:
>ag -Ri apache
will produce tons of matches like this one:
3:// Licensed under the Apache License, Version 2.0 (the "License");