By this message I will share some info about checking the condition of your newly purchased used probe.
FLUKE advice that the very specific probe at 40KV as also the one at 15KV, both have an resistance between the probe tip and the ground lead that is 999 M Ohm (1GΩ) which is a huge number.
To measure that resistance it is possible, if your handheld multimeter this supports measurement in nano Siemens
NS1GΩ=1nS
Multimeter list capable for nano Siemens:
BRYMEN BM869
FLUKE 28II / 87V / 8050A
AGILENT U1272A & U1273A
HIOKI DT4282
By measuring the two pins in the banana plug I measured 1 M Ohm, which all meters can do that.
Bellow is the
nano Siemens pulse of how it looks in my oscilloscope.