I noticed an issue when building a turret and it kept saying power failure when it shouldn't have.
So I tore the weapon apart and made sure no reactors or anything was in it.
The base has 22M power cap and 4.7M production/sec
So I noticed that the power was stuck at 6000/5000 and no recharge was going on at all.
I made a small ship then and added a capacitor to it and docked and it no longer filled up as it did when rail docks first came out. There goes all my charging stations down the toilet :)
The weapon system does fire and draw from the station it and any other docked vessel do not recharge capacitance when docked though. While it fires fine when a person is in the turret when AI take over it fires 1 shot assuming that has to do with it looking at the power failure.
I am assuming it shouldn't get a power failure as long as the system it draws from is capable of sustaining the load.
I've put the station up for download on the forums so you can try it if you want yourself. It is listed as the Pirate Barn.
So in truth it appears to be two issues found at one time. The ships 1e not working and improper recharging when docked.
I can't say if it did or didn't work every time between the first rail publish but it did work the first time rails was out.