Personally when I get a male platy that constantly chases females into hiding as fast as they try to venture out, I would get rid of him & replace with another,
I've run into it more times then I care to remember,
Peace always returns once the male aggressor is removed.
Those males will usually end up choosing one female as his favorite and she is allowed freedom to swim about unsuppressed.
I've got another case and point right now that i'm going to have to remove the old male.
In my 20 gallon right now I had an original pr
of platies, They always stuck together, the male mostly ignoring the other female platies, Just not allowing them within his or her personal space, However I lost the female abit ago and I've noticed the old male start requiring the young girls farther away from him, It's not uncommon to look into the tank and see no movement other them him alone, when one sticks its nose out of hiding he sends them back in a fluster.
I'm going to have to remove him and harmony will immediately return.
However what your describing may simple be the natural events of the mating ritual the male preforms almost constantly for the females attention and favors.