When shocking your water it's best practice to always remove the Sutro monitor (and everything else) from the water for 24 hrs or until sanitizer levels return to normal.
Shock levels of sanitizer can alter the appearance of the Sutro monitor, and it can also bleach the sensors, causing inaccurate chlorine readings immediately after the shocking has been completed.
If using a normal dose of non-chlorine shock (Monopersulfate aka MPS) it is ok to leave the monitor in the water but know that your chlorine test results may be skewed if the MPS hasn't fully dissipated. If you are double shocking then we recommend removing the monitor prior to adding MPS.
An alternative you can try when shocking the pool is to just put the Sutro into a bucket of pool water while the shock is treating your pool! This will still allow the Sutro to stay online without having to enter the portal and pause your readings for a few hours.
Lastly, keep in mind, the Sutro monitor only measures up to 5 ppm Cl2. In order to measure higher levels of sanitizer, we suggest using a test kit containing the FAS-DPD method or a test strip that measures higher sanitizer levels.