Show Manager play position not working (TEST BUILDS)

[Ceno]

Hi,
This is related to the 4.12.x builds on WIndows 7 - not sure if this is allowed/useful so if not please delete.

I downloaded 4.12.0.122 and the previous two versions and they all exhibit the same behaviour. I'm using Magic 3D Easy View to see the output :

Create four generic RGBW fixtures
Create a show
Add a track
Add a sequence where each fixture is turned on for a few seconds in turn
Run from start of show - no problem
Place the playback head in (for example) the third element of the sequence and hit play - the show lights start from first element, as if it isn't registering where the playback head is.

This works fine in 4.11.2.

Thanks.