Seen when loading an existing world after updating from 4.2.2 to 4.3.3 (Marooned modpack 1.1.0 -> 1.1.1). I think this would still be an issue with current master, but haven't tested it.

DataReader.readData() is getting called (from Team.loadData(), line 857) with -1 as the argument. This becomes the initial value of bitsLeft, which in turn is not a valid index into theBIT_MASK array.

• Forge v10.13.2.1307
• crash report
• players.dat hex dump / base64

Closed due to no longer supporting 1.7.10, please check if this problem persists in the latest 1.9.4 version. As networking and saving is rewritten for these versions the issue should be resolved.