MD4 Low Side Outputs

I have multiple MD4-7 low side output permanently latching off when it is driving a relay after a month or 2. Over the course of 2 years this seems to only be happening on the last few units I received, but not on any of the older ones. The current maximum on the output is 300ma and the relay I'm driving has a maximum inrush of 350ma for less than 1us, and it has a built in surge protection suppressor diode... I would normally say ugh I should have been more careful but I have quite a bit of units with all the same relays driving off of the same outputs without problems. has there been any component changes in the past couple months to these units? Anyone else have any thoughts on what might be happening?