OK, I found a way to lock it.
First off, let me say that you’re right. I couldn’t get the BT to hold indeffinately, even with hold and release decay etc all to max.
However, I did manage to do it with an LFO. That being said, it’s not super useful -you’ll see why (or maybe it is?).
After a kit reset I maxed out the usual suspects (hold, decay, release). In the LFO I put the depth to max. Then I chose the TUNE parameter on the LFO. For whatever reason this locks the sound indefinitely. That being said, it’s not really useful as it just wobbles
If you turn the depth down a little the sound will decay again.
Maybe there are other LFO params that will lock the sound but I didn’t find any…