One thing i dont do is bet my life on used diff probes if applied to high voltage lines
I'm a technical professional, I revise this probes during the wire "replacing" ant test the HV input part for leakage.
There's simple hi-Ohm dividers on inputs there no chance to broke with possible operator harms
..
Of course, i do not use, just purchased as a "parts" probe, on High Voltage, only after check)).