Is it possible for a masternode to arrive in its position of receiving the reward, but not receiving it, even though its last payment registered in the listing column is in the dash core? Why would a masternode skip his payment? On what occasions can this occur and how often?
This was much more a problem with our old masternode payment logic, it could happen that masternodes either did not get paid (unlucky masternode) or got paid twice (winning the lottery / lucky masternode). With our new deterministic masternode system that is no longer the case. As camosoul already mentioned, masternodes now either get paid or get de-listed / kicked from the network.
The PoSe Penalty score show a possible problem with masternodes (0 = no problem), if a masternode PoSe Penalty score gets too high it automatically ends up in a PoSe ban status.
Which is the 'delisting / kicking of the network' part.
Link :
https://www.dashninja.pl/deterministic-masternodes.html (to see the PoSe Penalty scores of the masternodes)
https://docs.dash.org/en/stable/masternodes/maintenance.html#proof-of-service-bans (to get a more detailed description of the PoSe ban)
https://docs.dash.org/en/stable/masternodes/understanding.html#proof-of-service (to get a more detailed description of PoSe)
The largest impact on PoSe Penalty score will be failure of masternodes to participate in DKG (Distributed Key Generator) --> 66% punishment
Current number of active masternodes : 4642
66% of 4642 : 3064 (rounded upwards)
PoSe Penalty score for failure to participate in DKG : 3064
Looking at above situation :
If a masternode with a PoSe Penalty of 1579 or higher gets another large PoSe penalty (for example due to failure to participate in DKG), it will automatically ends up in PoSe ban
(1579+3064 = 4643 = exceeding number of registered masternodes)
If a masternode with a PoSe Penalty of 1578 or lower gets another large PoSe penalty (due to failure to participate in DKG), it will not get PoSe banned just yet.
(1578+3064 = 4642 = not exceeding number of registered masternodes)
That masternode can still bring down its own PoSe Penalty score over time.
** Above calculation is my own interpretation of when PoSe ban occurs exactly, please have someone correct me if those numbers are incorrect **