Using Halion 6 / Sonic in two different programs

I was never be able to use 2 instances of Halion in two different programs at the same / when opened at the same time, on a single computer. Even if I use Halion 6 in one and Sonic in the other. Just would not open the second instance until I close one of the programs. What seems to be the issue?

If there is a licensing issue when using 2 Halion 6s or 2 Sonic items, that is wrong, but could be justified in some obscure way. But using Sonic in one program and Halion in another at the same time should not be an issue…

Can anybody shine a light on this for me please.

Thank you.