I have a little clip on YouTube on how to keep your bridge straight. There are many reasons why bridges can warp.
- Humidity is a very big factor. Very high humidity it does not matter how well made, how seasoned & high quality the timber it will warp fast
- Badly filed grooves or winding of string broken at the bridge will pull the bridge more
- Always clean the strings and the top of the bridge after playing, that way the rosin dust does not make the strings stick in the grooves
- When the bridge top has moved in either direction and it does not get corrected it will warp
- Either if the neck angle is wrong, the saddle too high or low in short if the angle the strings are running over the bridge is that uneven so the bridge top gets pulled in one direction.
- Too high tension strings or a too high bridge due to a high neck angle
The best way of preventing it to warp is always keep your cello bridge stand straight as shown in the video