DR15b5 Unstable

Unlike the betas before b5 has been quite unstable. I get freezes for no particular reason. Film Convert plug in does not work. I have now gone back to 15b4 and all seems to be good.
https://forum.blackmagicdesign.com/
https://forum.blackmagicdesign.com/viewtopic.php?f=21&t=75389
Uli Plank wrote:Film convert is working fine for me on a very similar, even a tad slower machine.
Why are you not using MacOS 10.13.5?