Could it be anything to do with battery fully charged it a few days ago so don't know if the charge was low or not.
Not if you read up on lipo saftey.
A lipo when it discharges does it in a very predictable way.
It starts off with a steep voltage drop from 8.4v to about 7.5v, but then levels out for most of the capacity of the battery 7.5v-7v. Then falls off again very quickly when it's almost done and give an shot by shot slowdown (you should pull the battery and swap it out as soon as this starts to happen).
You shouldn't see much variation in gearbox cycle times once it gets past that initial drop off. It should be a stable fire rate. Once it hits the final part of the discharge again you will notice it as significant slowing of the gearbox, but it won't stop shooting it'll just cycle slower.
1300mah is pretty low capacity, so if you were shooting it a lot after the first charge before the skirmish you might have gone out with a battery at only half charge. And if you have taken the battery to the bottom of the capacity into the range where it can no longer cycle the gun and was going very slowly then you might of done significant damage to the lipo. You have to watch them and swap them at the start of the final drop off.
If that is the case you need to measure the voltage of the lipo. If it is showing less than 5.8v it might be unsafe to charge . And it needs charging on a proper charging station that can refuse to charge a depleted/unsafe lipo. Rather than a cheap charger. Your skirmish site will have one of these if you don't.
The gun would completely jam as if its in safe, then I would switch to auto then back to semi to fix it.
This sounds like the saftey lever is jamming in the safe position, it probably getting caught on a wire and not falling off properly. It'll need the gearbox opening to check. You have a warranty use it. The video looks to back that up.
The battery in the video looks to be fine BTW, But it's worth leaving that statement up there^^ to remind you how dangerous lipos can be. If you only have the 1x 1300mAh battery get another so you can swap it out when it starts to fall off.
Send that video to Patrol base. It's good evidence and shows the fault as a fault. They will have to act on it. But you also need to do another video without spamming semi. To prove it's not you spamming causing the issue.