Akward return values from opt3001::readRegister

[CCommander]

On the MSP-EXP430FR4133, I get strange return values from opt3001::readRegister, if I do not mask the msb and lsb after reading through wire.read.

My workaround:

msb = Wire.read();
lsb = Wire.read();
result = ((msb&0xFF) << 8) | (lsb&0xFF);

[rei-vilo]

How msb and lsb have been declared? They should be uint8_t.

[CCommander]

msb and lsb are int8_t

They were not declared by me. OPT3001.cpp as a library is part of Energia.