Minimum load current is the least amount of current that the SSR will switch on and continue to carry with a nominal output voltage drop. Load currents less than this value may not be switched by the SSR. Typical minimum load currents are 50 to 100 mA rms.
One means of determining that there is a potential compatibility problem, aside from published specifications, is that the forward voltage drop across the relay will be in excess of the specification. Another means is that the load does not fully turn on or operate correctly. This is due to excess voltage drop in the SSR because it is not able to turn on fully.
A RC snubber network adds leakage current to the SSR. In cases where loads are very light, the snubber leakage current can become a significant percentage of the total load current. E.g.: a SSR with snubber leakage current of 10 mA would be 25 % of a 40 mA relay coil or solenoid. Generally, that is enough current to keep the load latched on. The best choice in such a case would be to employ a SSR with out a RC network, or at least an SSR with a small RC network. The alternative is to add a parallel bypass shunt resistor around the load to decrease the leakage current component going through the load.