Keys that start with digits are being cast to int because of:
https://github.com/phpredis/phpredis/blob/develop/redis_commands.c#L2689-L2695

You are calling is_numeric_string() with allow_errors = 1 which means it will take a hash key like
"86deaeb05e3f7760b67e92897a1325e0fdd8618d" and return IS_LONG with lval = 86.

I'm assuming that was not your intent.