How to get the time for which the metric became maximum in Prometheus?

Question

Monitoring

Can you tell me if it's possible, and if so, how?
There is a metric that we give to prometheus, at some point in time it changes from 0 to a certain maximum value (let's say 100). The task is: to get the time for which it grew.
I tried like this:
some_metric{label="l1"}[10m]- the interval during which the maximum value is usually always reached

timestamp(max_over_time(some_metric{label="l1"}[10m]))- timestamp(min_over_time(some_metric{label="l1"}[10m]))

- in this case, 0 is returned because, for reasons that are not clear to me, the expression:

timestamp(max_over_time(some_metric{label="l1"}[10m]))

and

timestamp(min_over_time(some_metric{label="l1"}[10m]))

return the same value, although :
min_over_time(some_metric{label="l1"}[10m])
and
max_over_time(some_metric{label="l1"}[10m])
returns the maximum and minimum value for the specified period