TL;DR: Same answer as the rest - not normal for your CPU. But now with authoritative sources, yay!
For Intel 12th gen CPUs, this is not normal. The relevant specification (careful - PDF download) found at the Intel's website clearly states (with minor edits for brevity):
The PROCHOT# (processor hot) signal is asserted by the processor when the TCC [Thermal Control Circuit] is active. [...] When any DTS [Digital Thermal Sensor] temperature reaches the TCC activation temperature, the PROCHOT# signal will be asserted.
And then (emphasis mine):
With a properly designed and characterized thermal solution, it is anticipated that PROCHOT# will only be asserted for very short periods of time when running the most power intensive applications. The processor performance impact due to these brief periods of TCC activation is expected to be so minor that it would be immeasurable.
However, an under-designed thermal solution that is not able to prevent excessive assertion of PROCHOT# in the anticipated ambient environment may:
- Cause a noticeable performance loss.
- Result in prolonged operation at or above the specified maximum junction temperature and affect the long-term reliability of the processor.
- May be incapable of cooling the processor even when the TCC is active continuously (in extreme situations).
IF all these measures fail, and there is a risk of physical damage to the product, another signal will go off:
[...] the package will automatically shut down when the silicon has
reached an elevated temperature that risks physical damage to the
product. At this point, the THRMTRIP# signal will go active.
Relevant conditions are not elaborated, but typically you could expect a "hard" shutdown as late as 115-125°C and as early as 105°C (lower limits are coming from my anecdotal experience). At any rate, temperatures above 125°C are generally seen as extreme, and are a part of industry-standard stress tests such as JEDEC HTOL [high temperature operating life] (pdf download!).
It is important to note that for modern CPUs, there is more to it than just temperatures. Intel tries to cool off long before reaching Tjmax (maximum junction temperature), and the throttling behavior is entirely centered around that temperature. In particular, when trying to go over it, a complex network of regulation of clocks, power limits, C-states and so on will be engaged. For Alder Lake desktop CPUs, Tjmax is 100°C, and this is the temperature referred to in the datasheet above.
By contrast, Ryzen 7000 series reaches Tjmax early and dances around it, boosting opportunistically and throttling as needed, relying on your thermal solution to do its job. Here is a promo/explanatory post from an AMD representative elaborating on this behavior. It also makes sense: larger temperature differences mean more efficient cooling. The main reason this approach is not widespread is because it becomes harder to control, with tiny margins for error. AMD is confident in their ability to keep temperatures under control, and time will tell whether they are right to do so. The reason I bring this up is because "high temperatures=bad" approach is currently being hotly contested: it is kind of like taking a corner in a race car, for a reasonable driver, there is no point in slowing down late - benefits are slim, and the price to pay is high. But you could go faster by taking more risks, which is what AMD does, and the question then becomes whether they can reliably handle it or not.
Either way, whether a given behavior is fine for a given product or not can and should be determined from the relevant design documents. And in your case, hitting Tjmax for a prolonged period of time is specifically described in the datasheet as an indication of an under-designed thermal solution.