Cycle on degrees-minutes-seconds value contains invalid notation

[mahi2003]

Enter a dms value like 1°30'00" on the stack. Now press Cycle (E) repeatedly:

1/120 πr
1 1/2 °
1 2/3 grad
0.02617993878 r
1.66666666667 grad
1.5 °
0.008333333333 πr
1°29'59"1 → ❌ What's this?
1°30'00" (back at beginning)

The 'weird' dms value is always 1 second less + a 1 behind the seconds mark. Pressing down arrow (edit) on such a value and then ENTER gives "Syntax error".

I noticed that DB48/50X can display fractional values after the seconds (for example 1°30'45"1/2), so I think it's trying to display 1°29'59"1/1, but that does not really make sense.