Omission at Supertransmuting King?

[WalterL-wL]

While experimenting with this fairy condition in a) two different results were presented by Popeye v4.89 - but I cannot see WHY there should be a difference at all:

The problem (German notation, H = Locust):
anfa
ford#2
bedi SchwarzerSuperTransmutierenderKoenig
bedi WeisserSuperTransmutierenderKoenig
Forsyth 3k4/bb1bl3/BB1b4/H2K3b/8/8/8/8
Opti vari zugn
zwilling Forderung s#2
Ende

Popeye shows the following result:
a)...
9 (a6×b7 Zeit = 0.156 s)
10 (b6×a7 Zeit = 0.172 s)
1.b6×a7 ! Drohung:
2.a7-a8=H# (correct; but where is the 2nd, if 1...Kd8-c8??)

As soon as you change Ha5>c4 the results presentation extends, but WHY only then? In my opinion the result(s) are NOT influenced by the change of position of the Locust? (Forsyth 3k4/bb1bl3/BB1b4/3K3b/2H5/8/8/8):

a)...
8 (a6×b7 Zeit = 1.202 s)
9 (b6×a7 Zeit = 1.202 s)
1.b6×a7 ! Drohung:
2.a7-a8=H# (correct)
1...Kd8-c8
2.a6×b7# (!!! 'coz bKc8 checked by wPb7 cannot move as a bP)