PTC v66 - Extremely slow load time on larger unreal game

Large UE games are incredibly slow to load on v66 (like 25 seconds)

The same apk/obb loads in around 3 seconds on v65 and earlier. It's built against the v65 SDK. Something really weird going on with v66. I also notice sometimes OS apps are hanging/going really slow to load (like airlink)

To reproduce install asgards wrath 2,

First run is a bit slow but normal, compiles shaders etc.

Close it

Second run sits on the ... screen for 25 seconds then loads. Same for all subsequent runs.

[EDIT] This appears to be to do with the app's apk signing certificate. A load of errors in the log are occurring for the 20 second wait.

 Certificate buffer not long enough, returning

 If I rebuild my app with a new certificate it then works but I can't change this on the store