Yes, v6.35 returns the expected $gmt times.

You have included a number of observations after the above sentence... I am going to assume that they illustrate that $gmt(N) in v6.35 is fully working the way you expect.

So, if v6.35 is working the way you expect, it looks like a previous scripter was trying to do something with $gmt(N) that was not giving the result they expected and requested that it be changed to the current behaviour. Considering that $gmt(N) is not documented, that seems fair enough.

Unfortunately, the scripter may no longer be around, so there's no way to know why they requested this.

In this case, the old code from v6.35 is actually still there, just commented out, so I could change it back. But... can you think of a reason why the current behaviour would make sense?