Kdenlive-18.04.2 running on Slackware64-current (x86_64) with KDE 5 and Intel graphics.

I've just finished editing quite a long video of a charity gig for some friends. Everything has gone smoothly until I come to make up a roller caption for the end credits. No matter what I do, I cannot get the colour right!

All the other captions are in saturated yellow with a black shadow. If I set the same colour for the roller, it looks fine when composing it, but as soon as I click on "OK" to save it, the saved version turns to green!

The only colours that don't change are the primary ones, red, green and blue. Any other colour doesn't work as composed.

Looking at it on the vectorscope, instead of the expected single colour (yellow), there are two colours - almost like a PAL vector - showing both yellow and cyan, with an average somewhere in the middle:



Nothing I have tried will give me a clean yellow to match the other captions. This only happens when I try and animate.

Any ideas, anyone?

--
Pete