Help with Automatic Transmission issue

Bilazaurus

I'm kinda desperately looking for help with my 13' Z AT. I started to notice some issues about 1k km ago since I had Whiteline diff bushings installed. The problem is like this.

1. When on Drive(automatic) and coming to a stop it sometimes jerks slightly when AT is downshifting from 2nd to 1st. It's just noticeable, like pressing very slightly brake pedal. It does it about once per five downshifts and is rather irregular and only when car is warmed up. Only once it was very noticeable like a poorly executed MT downshift. I almost never downshift manually to 1st gear, and only in 10kmh range or so.

2. This worries me the most. When shifting from Drive to Park it can shift violently. Sometimes noticably, sometimes it's very audible and jerks the car with a thump. Only once there was a very loud thump and once there was a thump when I was already on Reverse and reversed about one meter. The latter happened on cold, former on hot. It's more irregular than issue #1 and there is no rhyme no reason. Going from Park to Drive never produces any issue. It's smooth and inaudible.

3. Very rarely manual downshift from 4th to 3rd is slightly delayed

4. Going from 2nd to 1st (auto mode) produces a click sound. It's also audible when going from Drive to Park

5. Right away after installing Whiteline's diff bushings I noticed shifting being slightly harsher but I address it to harsher diff engagement due to harder bushings.

Otherwhise, my AT shifts fine and smoothly from 3rd to 4th and up. I don't experience any slippage and car accelerates as it should. Right away after installing Whiteline's diff bushings I noticed shifting being slightly harsher but I address it to harsher diff engagement due to harder bushings. I've changed AT oil about 200km ago and it didn't really help. The only mod that is worth mentioning in this situation, beside bushings, are more aggressive JUN exhaust camshafts. Could electronic AT valves be the culprit?
I'm sorry for creating another topic but I've searched through and through and couldn't spot identical issue. Thanks in advance.