Cascading voltage regs not working as expected
Three-terminal linear regulators usually can't sink current - the 5 volt regulator can't pull the ground terminal of the 10 volt regulator down.  It can only pull its output up to 5 volts.

If you put a small load on the 5 volt line, that should pull the 5 volt line back down to 5 volts (if the load draws more than the 10 volt regulator's ground current).

If you are drawing any significant current from these regulators you will need a good heatsink.

I haven't look at the datasheet for those regulators, but you probably need input and output capacitors close to the regulators.