Playhead does not stop when hitting spacebar or Toggle in the program window.

Hi, 

I started my project a year ago and started with the Beta version. Sometime there where a view bugs but never for more than 1 or tow days. I am working in version 25.6.0 Beta (build 36)

SInce 1,5 weeks ago my playhead won't stop when I hit the Spacebar or the Toggle in the Program window. I have to wait for about 30 seconds or longer before it stops. 

I do'nt have the same problem when I am working in the Source window. 

I am getting closer to my deadline so I start to get a little nervous about it. 

Hope you have a solution for me. 

Thank you in advance,

Marc Waltman