As per Northwind I’ve also found that they need riding to seal

I’ve also had the cheap square bottom tubeless valves separate from the valve overtime 🙁

(Only problem with an airshot is once you get one you tend to go tubeless on everything it really does work well no more spunk sprayed over the place like a really bad porno.)

In all the time I’ve been tubeless its cost me 1 tyre. That’s it. Some time I admit.
I have 5 other tyres all tubeless and no issues, 4 of them have been taped by me.

I did one the other week, sweating my nuts off with track pump, wouldn’t go up for love nor money…. then remembered I had CO2 in backpack…. no idea how quickly it inflated but it was in milliseconds.

For the times I change tyres, a couple of quid for cartridges is cheap.

If you are using Stans, then there is an even chance you have wrecked the sealant. It doesn’t react well to cold and C02.

If you have to use Co2 then just use it to set the bead without sealant in, then let the air out, add sealant and reinflate with track pump.

Fortunately was aware of that, and had already let it out, only use it to seat bead.

After that, remove valve stem and put sealant in.