[Elecraft] KX3 - selfprogramming macros - why does PF1 work ok, but not PF2

[LA3RK - Olaf]

I have made a macro assigned to PF1 which sets the KX3 in split mode 
with subrx. The macro is followed by some commands which reprograms PF1 
to remove the split and revert to single RX by setting PF1 to macro 2 - 
this works fine and allows PF1 to both turn on and turn off split. Macro 
2 does the reverse and reassigns macro 1 to PF1 - thus PF1 works as a 
toggle between split+sub rx and no split.

For PF2 I am trying to make a similar setup to allow two macros on the 
same button, the critical commands are;

To reprogram to macro no 4 (just the reprogram steps shown): MN110; 
SWT28; SWH26; MN255;
Or said differently; enter macro x, tap 4, hold PF2, exit
To reprogram back to macro 3: MN110; SWT20; SWH26; MN255; (enter macro 
x, tap 3, hold PF2 and exit)

For some reason I am not able to make this work on PF2, the same 
sequence works fine on PF1 but I am not able to make it work on PF2. I 
have similar commands on my K3 and they works on all programmable buttons.

Can anyone spot an error in my logic or have I met a bug in the KX3 
firmware?

73 de Olaf - LA3RK