Render issue with title animation in DaVinci Resolve 15

Hi guys, i'm new to this but enjoying learning how to use DaVinci.

I'm having an odd issue. I've edited and graded a video, and have inserted some titles using the Lower3rdSipmpleBoxThin preset. It plays back exactly how i want it too when i review the film on the "Deliver" screen, but the final rendered file does not animate the titles the same way as it plays in DaVinci. Rather than the title being on screen for 2 seconds for example, it flashes on and off briefly.

Any ideas as to what I may be doing wrong? As i said, the play back on the Deliver screen is perfect, it's just the final file that changes.

Thanks
D

When you are rendering out from the delivery page have you selected individual clips or a single file?