Slime not sticking properly to Powered Rails from underneath

Release_1.2.3 516590
Summary:
When a slime block is pushed and it has a powered rail on top of it, the powered rail breaks.
Impact:
Not consistent with 1.2.2 and other versions. The powered rail in prior versions would move as it should and not break.
Repro Steps:
1. put down a piston facing a slime block
2. put a powered rail on top of it
3. power the piston

Observed results:
powered rail pops off
Expected results:
powered rail should move with the piston
Screenshots/videos attached:
https://youtu.be/UxLPLddzPQo