It is impossible to deliver the same check three times in Mansindam. This is because three fold repetition includes perpetual check.
Not true. In the following diagram black (on move) will have to play 1... Rxc8, at which point a position arises for the first time (as it was a capture). After 2. Qa6+ Kb8 3. Qb6+ the only black evasion would be 3... Ka8. But this repeats the position after 1... Rxc8. So black is the first to repeat, and white is allowed to check three times by moving his Queen between a6 and b6. Because the third time he does it the black King is still on b8.
With Masindam rules black would have lost here, because he will either repeat too many times, or must stay in check. With the rules you let Stockfish play by, white would lose here, because he is perpetually checking.
Not true. In the following diagram black (on move) will have to play 1... Rxc8, at which point a position arises for the first time (as it was a capture). After 2. Qa6+ Kb8 3. Qb6+ the only black evasion would be 3... Ka8. But this repeats the position after 1... Rxc8. So black is the first to repeat, and white is allowed to check three times by moving his Queen between a6 and b6. Because the third time he does it the black King is still on b8.
With Masindam rules black would have lost here, because he will either repeat too many times, or must stay in check. With the rules you let Stockfish play by, white would lose here, because he is perpetually checking.