I've had this problem too. I use RB and not PT but if PT is 32 bit, as RB is, I have a solution for you.

I've worked quite a bit with Joao on this, he is the developer of jBridge. The problem is not how SampleTank 4 or PT is responding, it's how jBridge is configured.

To setup SampleTank 4:
1. right click on the track you want to add SampleTank 4 to.
2. Click on "Add specific VSTi or DXi to the MIDI track" from the pulldown
3. Select SampleTank 4 from your loaded .dll's
4. On the track header in PT, click on the blue "Edit Vsti Fx button" to open SampleTank 4
5. At the bottom of the SampleTank 4 display, click on "jBridge settings". Up may have to scroll up to see this at the bottom of the SampleTank 4 display.
6. In the jBridge setting dialogue, click on "GUI always on top" and "audio Master Get Time Hack"
7. Close all windows and close PT or RB
8. Reopen PT or RB
9. Now assign SampleTank 4 to your track, select ST4 instrument you want to use
10. On the volume or pan ST4 slider, right click to pull up MIDILearn and follow the popup instructions to get ST4 to control volume and Pan in RB / PT

Let me know if you have success.

Jeff

Win11, Intel i7 7700K 4.2Ghz, 32Gb RAM, 2x1Tb HD, 500Gb NVMe, BIAB/RB 2025, MOTU 828MK3 audio, MOTU Midi Express, Yamaha Montage 7, DX7II, TX802, Motif XS Rack, Roland Fantom XR Rack, Oberheim Matrix 1000, VoiceLive3 Extreme, Kontakt 6, SampleTank 4.3