Hi @virtualdxs,
welcome to Sonic Pi and to in_thread.
(It’s quite helpful to post the code so others can try it out. You can start with 3 backticks in the first line and end with another line of 3 backticks. This will show your code nicely formated.)
But, as far as I understand from your description you are stumbeling on an implementation detail which somehow causes trouble for quite a few users. If I am right, this thread might be of some help.
Let us know what you are doing with Sonic Pi and post some code (as soon as you ready for it).