Didn't your AVR go for repairs recently? Could be a lot of things but - to start the trouble shoot - I will first recheck all connections - clean up and reseat them all again.
It happens with my SR5015 as well but not consistant. Sometimes it runs longer without the any audio cuts and certain times it does it, To give a fair idea; while watching a 2 hour movie if it happens it happens for around 2 to 3 times. This is while the sound is output from TV with no inputs to the receiver.
Tv has a mind of its own, the audio equipment its own, the marriage is seldom perfect. Ironically none manufactures the other half and the story continues. Individually both function properly and their warranty is only onto themselves.
I dont think so. not really noticed but I can possibly relate to an experience where most new movies have that 1 sec pause of sound for action scenes and then the sound pours in. I used the TV only with Firestick for OTT content where this so called one second pause in audio output happens.
My suggestion is to try different content or watch some concert and see if the same thing happens. If it does then as suggested by other FMs, please troubleshoot carefully and if all does not work, maybe a reset may help (be sure before doing this). Last resort Service Center to investigate if its an ongoing problem.
What is your source? What are the speaker levels you are running and also the source gain set? Could something be clipping as you mention it happens during the Loud scenes?