In some rb's model 433ah, using cards R52 and R52 HN cards are physically connected, run a certain time and then disappear, some times this problem was solved after the downgrade to 4.17, and the problem was resolved, now no longer this ahead ...

occur in more than 10 different outfits, when exchanged solve the problem, but after testing the equipment samples found no apparent problem

RB's 433 ah
Cards R52 and R52 HN
Firmware 5.11 and 4.17