After one month of usage, my thermometer with probe started to give random results.
I was very surprised as it did work very well for the month I owned it. So I looked at user feedbacks on amazon.fr, amazon.co.uk and amazon.com for my model (eKitch brand) and I saw that I was not alone in that case.
But more interestingly, I noticed that many makes and models suffered from abnormal rates of random failures that looked similar to mine.
See for instance:
"Taylor 1470 Digital Cooking Thermometer/Timer"
"CDN Digital Programmable Probe Thermometer"
"ThermoWorks The Original Cooking Thermometer"
All these models seem to share the same Achille"'s heel: the probe itself.
So far, I haven't figured out what makes it fail, but until then, if you shop for an oven thermometer with probe (a tool that I otherwise find extremely useful), skip those models with that sort of probe, it's junk.