Tamiya Acrylics - Masking

[Neonblau]

Looking for a bit of advice.

I've recently done a couple of paint jobs that required masking up of hard edges. I'm using Tamiya acrylics, thinned 50% for airbrushing (X-20A thinner), with fresh Tamiya masking tape. I've made sure the tape has been well stuck, flatted etc. and have sprayed at right angles to the surface.

I'm getting what appears to be "creep" under the tape, in some places almost the whole width.

Any ideas what is happening - is it paint concentration, spray pressure or something else?

[Neonblau]

Thanks for all the tips - dr_gn, I did feel the paint mix was way too thin and I'm now using about 25% which goes down better.