Sounds a bit of a mystery, unless you have installed the cartridges in the wrong slots!.
Having two different make printers, doing the same 'error' would nigh on be impossible, unless the above is correct, or the program that you are using for the printouts, is faulty in some way. Have you used the program previously with good results?.
Both Epson and Lexmark have good technical back-up, so why not contact them for further advice, or you could try click here
Regarding the Epson,and perhaps the Lexmark (if still under warranty) you could refer the matter back to the retailer's, and see what their response is. Epson usually do a swap-out on any faulty units, but in consumer law, the retailer is the first link in the chain for consumer satisfaction.