Here's another (bizarre) scenario:
I had two devices connected in bluetooth, a BTR7 and a BTR15.
The BTR7 was in AptX adaptive and the BTR15 was in LDAC.
Music coming out on the BTR15 (so LDAC output), I get the same audio hiccups as if I was only outputting through the AptX adaptive one.
Disconnecting the BTR7 (turning it off), stopped the playback (ok, edge case I guess), I restarted playback and everything is fine (now on BTR15 in LDAC).
Side note: both devices can do LDAC, the issue is when wanting to use it in a crowded place, with a lots of interference. LDAC is not the best for this.