If we configure in Freemaster 188.8.131.52 a bitmask to a 8byte (64bit) variable, it doesen't work. The bitmask has no effect to the value.
thank you for reporting this. I confirm two issues - will address it in the next release:
Reading a 64bit variable, shifting it and masking with a mask value limited to 32bits should work without issues.
As a workaround, you can define two helper 4-byte variables with an addresses "symbol" and "symbol+4" - and access them separately.