Fence paint 'splitting'?

sparrer

I'm painting 2 new fencing panels with Cuprinol forget-me-not blue to match the three panels which are already there. Two coats went on perfectly last year. Have just bought a new pot, put one coat on the new panels with no problems but the second coat is 'splitting' - covering at first then separating from itself, almost beading like rain on a windscreen - I don't know how else to describe it. The wood is completely dry and the brush is new.
Any suggestions as to what could be causing it please?
Tia.

Jack_Regan

They do say you should take previously treated wood back to bare wood.

sparrer

Not heard of this but I'll bear it in mind.
However as the first coat has gone on and covered well I'm perplexed as to why the second one won't, especially as I've used the same paint/wood before with no problems.