DaVinci beta5 alpha png-sequence problem

Hello, in new beta have flicker in alpha-channel in png-sequences. When reinstall Beta4 - it have not flicking.
Have any idea?
OFFTOP: Sorry for my English
Have any idea?
OFFTOP: Sorry for my English
https://forum.blackmagicdesign.com/
https://forum.blackmagicdesign.com/viewtopic.php?f=21&t=75650