Not sure where to post was hoping a vet would see this and be able to give some advice (have cross posted in a few subs)

Context: I have taken my cat to the vets twice over the last year, once when I first noticed the irregular breathing- she had scans done on her heart and lungs and I was told they can’t see anything, the second time she went it was for something unrelated but I asked them to check her heart and lungs again and they said they couldn’t hear anything wrong) 

What is happening to my cat in this video? This is now at least the 5th time I’ve seen her do this, there’s no pattern or regularity to it, the other times I’ve seen/ heard ger do it it tends to be at night. It’s like she’s struggling to breath? This only ever lasts for as long as it does in the video and afterwards she’s fine, she still eats/ drinks/ plays so I have no other indication that there’s anything wrong with her other than this and that she breaths through her mouth quite regularly but I only notice this when she’s purring (which is pretty much all the time). Another thing is that it’s visible to see when she’s breathing and looks as though it might be somewhat difficult for her but again this is not all the time. 

Further context: she is 13 this year so I don’t know if some of it is just age related?

This is the first time I’ve managed to get it on video so apologies for the music in the back ground and my worried voice.

Has anyone had anything similar with their cat or have any information that could be helpful?

Please don’t try and slate me as a bad owner for not taking her to the vets as soon as this happened or say things like she’s dying- I’m looking for genuine and helpful advice which I will do my best to act on.

What is happening with my cat?