Hi,
I was trying to use the search, but, well, I did not found any results, but anyway, sorry for double posts.
I did noticed, that I am not making any progress towards achievements as: Race 50 laps in rain/night at multiplayer and similar. I do play tons of league races, I dont want to play classic multiplayer lobby - tbh, there´s no reason for me to do so. So, will you fix it ? Because, for me, league racing looks like a multiplayer and it should count towards multiplayer achievements.
Agreed, it involves racing against other people, therefore it should count towards Multiplayer Achievements 
This has been the case since launch, however if you want to get those Achievements quickly you can set up a Private Lobby and select the appropriate track(s) to unlock them.
Having the same problem.It must be glitched because I have got the achievement for doing 100 lap in multiplayer even though have only done league racing so far.
Asked this here a while ago, in fact league rcing is not counting toward archivement in the moment. Have no info if this is working as intended or a bug. Form my Point of view it is a bug.
Same thing here with league but does count in normal hoppers so I assumed it is supposed to be that way, in no rush to get it though.