Yep. That's set too light. I have several Tikkas/sakos, that I set so they were all the same for consistency, but one would do this until set a little higher, it was at 14oz but now around 18oz, so I've now set them all at that. Too light means the sear either won't engage, or partially engages, allowing it to cock, but won't allow the safety selector to engage. You may find it's worse when cold as any lube is thicker so slowing it down in use.
Pete