The latest patch for DCS Black Shark has implemented a new and default trimmer implementation. It works like this: once you hit the trimmer button, any input from your joystick and rudder pedals will be ignored until you center them. Most of the times this new trimmer implementation works like a charm, but if you fail to center your joystick and rudder any further input from them will be ignored (controls lockup, yikes!).
If your joystick and rudder pedals are not properly calibrated/centered, these lockups will happen when you least want them. Joysticks and pedals generating a moderate amount of "noise" will also produce these lockups.
To avoid these lockups, I suggest you go into the game's option suite, controls tab, axis commands and click on the "tune axis" option. Once in the axis tune panel, provide a small amount of "dead zone" to the axis of your controllers. The amount of "dead zone" depends on how noisy your controls are.