large brush bug

I tried creating a large brush but the maximum it would take is 250 - If I tried creating anything higher , say 400 ( for airbrush ) the brush icon creates a default size of 15 each time .

Anyone else found this ?

I managed to create a brush of size 500 on Windows.

Try this - select a preset brush ( Say 100) - scale to 400 - add this brush to presets. ( This will work fine , once ) now select the same 100 brush and scale to 350 . When you make a new brush from this it appears in the brush presets as 15 .- its a bug . I have found workarounds but it needs fixing.
This is on a mac - I don’t know about windows.