Cause of broken lander legs on my rover? Kerbal Space Program

I made a rover for drilling, containing both wheels and landing struts (for support while drilling.) At first it worked fine, but as I was playing around with various wheels and configurations, I noticed during testing on Kerbin that one or two of my landing struts were breaking right as they were being extended. I put the old wheel configuration back on, but now the struts are still breaking when I expand them. I don't think it's the wheels, but I could be wrong. Sometimes it's the two front struts that break, sometimes it's just one (and not always the same one) even with no changes to the rover. Any thoughts on what might be causing this?
In this case, it's the leftmost strut in the picture (the front left one) that's broken. My engineer could repair it if he was level 3, but who knows if it would happen again, and on Minmus too...
Again I want to stress that I had several successful tests in the same area on Kerbin without any major changes. The only thing I added was some structural struts over the batteries (they were shifting a bit on bumps) and messing around with the wheels as I said before.
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How do you repair Rovers in KSP?
LT-2 Landing struts can be set to be either extended or retracted at launch. This is done by right-clicking the part in the VAB or SPH and clicking the relevant button.How do you extend landing legs in KSP?
The traction control value can be tailored to individual vehicles to prevent wheelspin in different conditions. Traction control can be overridden and a manual limit to the motor output set. Friction control can be overridden and adjusted on a scale from 0.1-5.0.8 STUPID MISTAKES everybody makes in Kerbal Space Program
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Images: Nataliya Vaitkevich, Eneida Nieves, Andrea Piacquadio, cottonbro