Are few UDMA_CRC_Error_Count errors in an SSD an issue?

Some SMART stats:

Device Model:     Samsung SSD 850 EVO 500GB
Firmware Version: EMT01B6Q
  9 Power_On_Hours          0x0032   099   099   000    Old_age   Always       -       252
 12 Power_Cycle_Count       0x0032   099   099   000    Old_age   Always       -       75
199 UDMA_CRC_Error_Count    0x003e   099   099   000    Old_age   Always       -       3
241 Total_LBAs_Written      0x0032   099   099   000    Old_age   Always       -       543780004

Host is a Thinkpad T420. Are UDMA_CRC_Error_Count = 3 at this time a problem?

Has anybody else this combination in use and sees similar behavior?

What exactly does this mean?

The good news is that the CRC errors you see are automatically and silently recovered from by the SATA controller.

Most often the issue is caused by a faulty, kinked, or poorly seated SATA cable/connection.

Don't worry about the count as it stands now (3 is a very low number), but do worry if the count increases over time. At that point you might try to re-seat the SATA cable/connection or replace the cable (if there even is a cable). In the worst case it could well be a faulty SATA controller on laptop or hard drive itself; in that case, well, you could try a replacement hard drive and failing that, a new lappy.

When (if) I find proper references for all this I'll update the answer. For now, you're going on my own personal experience ;-)

Reconecting/cleaning the connection solved the problem.