Pistons/sticky pistons with slime blocks on top power randomly

Xiaomi mi8
Before this version pistons with slime blocks on top power at the same time with the same tick, however now it appears to power a randomly selected piston instead of powering all at the same tick

Steps to reproduce:
1.put 4 sticky pistons in a square facing upwards
2. Put 1 slime block on each of the pistons
3. Connect repeaters with the same tick to power the pistons at the same time, use redstone to connect the repeaters to a unified power source
4. Use button to power the redstone