Bugs!!!!
Bugs, more Bugs, make it rain Bugs.
Ninja DC when you load up to 100% only to "start" the match at 5 minutes in? Check.
Stuttering for no reason? Check.
Visions not working properly? You bet, they still dont reveal all the area even when placed in the same area when just 1 minute before the ward revealed everything XD
Can't select wards? You bet ya, get a new ward and can't use it since Champ select won't let you select it XD (ironic to some extent).
Random Disconnecting of all players in the servers? Hilariously true, seen it a few times (my connection pretty stable and PC pretty powerful i get back on pretty damn quick, first than everyone else, hence i know the servers kicked everyone out ^_^).
Cast an ability, but deal with two delays (the cast time, and the servers being mean even when ping is stable as can be XD seen this a few times, it is funny, you literally wait to time things right after a while, kind of reminds me of the Cait bug).
Error messages for days in client, champ select? Virtually every other match!
Store not showing stuff right? Yep, Skins page blank, yet click on featured skins from featured tab and they pop up! Bugs!!!!!
And click a skin, mastery page, rune page and it reverts back to what you had previous match (skins default the last one you used, while runes and masteries literally the match before so if u were adc ur ahri has ad runes and masteries)? Now this happens every once in a while, but noticed it pop up more as soon as Pre6 started.
Also, the chat blocks when you are first to enter lobby!
Entering Champ select causes a "loading" to pop up.
Entering Champ Select causes champ info to block lower half of screen, gets off after you choose a champ.
I noticed similar issues PreSeason5 (like half of what i mentioned), i cant wait for the maintenance (which seemed to really help with this stuff).