There is a problem with the ClientRandomId(CID) of the client data contained in the LoginPacket.

Recently, I've been experiencing a problem where some of the Android users have the same CID.
The value of the CID is consistently 9223372036854775807, which is the maximum value of the BIGINT.

And what is written in games/com.mojang/minecraftpe/clientId.txt has not been validated.
If there are any characters other than numbers, they seem to be ignored.
Here are some examples: (tested on Windows 10)
5744c044cd30 → 5744 (clientId.txt was not overwritten)
ILoveMojang<3 (clientId.txt was overwritten)

In addition, the CID sent is not the same as what is in the file.
example: (tested on Windows 10)
in clientId.txt: 3345431947655838679
receinved: -6143449825213770105