When using a Pulse weapon system, it seems that, if a second pulse is applied to a target entity before the previous one has finished its explosion calculations, there comes a point where any pulse system on the firing ship no longer register to any other entity.
This appears to be most apparent when using Pulse/Cannon systems, with high rates of fire. Relogging client-side does not restore normal function. Restarting the server does appear to correct the issue temporarily, but does not prevent it from happening again.
Tested on a derelict station and asteroid both in separate sessions. Once the bug occurs, recovery is not possible for the same firing entity until the server is restarted.