Tool Preset Issue

[Just Fred]

I create a new pencil tool preset that is a simple 15 x 15 pixel square and save it as Square 15. I create another pencil preset tool that is a 25 x 25 pixel square and save it as Square 25. When I go to use the tools the Square 15 tool has changed to 25 x 25. Both tools are the same.

I've created tool presets in the past without issue. Is there some check box or preference or option I have failed to set?

Using Gimp 2.8.10

Thanks Fred