After re-reading c903' s post I went back & inspected the shafts - you know what - I bet he' s right - in that it' s a reaction with either the acetone or the glue (in this case the goat-tuff)...

The end of the vanes really have a curl AWAY from the shaft - unlike I' ve ever seen - AND - I dropped a dab of tuff on the end to help hold them down - I wonder if it' s the glue or acetone...

I' ll listen to the ' man' tomorrow & get his advice before I waste another 18 flex fletch vanes...

Thanks for the input fellas - !