Distorted music when using sound check

This question has been around for some time, but I have not seen a definite/credible answer, based on either measurements or Apple insider knowledge. See for example this entry in another forum: Apple Music Sound Check Feature: Likely Audible Degradation or Not? | Audio Science Review (ASR) Forum

My question: To what extent, if any, does Sound Check (under Apple Music settings on iPhone or iPad) impact the sound quality of "lossless" music (either streamed or stored locally)?

The standard reply, i.e., that the level (of a song) is adjusted in a manner equivalent to tweaking the regular volume slider, was NOT true a few years ago: Some songs would be seriously distorted when Sound Check was switched on. (Personal experience, plus that of others).

Adding to the confusion, it has been claimed that Sound Check works as intended for "lossless" music, while still broken for AAC.

Does anyone know whether the Sound Check feature been corrected in a recent iOS update, such that the above (standard) reply is now true, or should I still avoid Sound Check if I really care about enjoying the quality of lossless music?