Me too! I think it probably is.
After spending a good few hours trying to trouble shoot, disconnecting about half the wiring, it wasn't the switches or the wiring as such. I had attached dropper wires to the tabs under switch blades of the Peco Insulfrog points as it was easier than trying to attach to the track. This was causing some of the problem. When I isolated those wires things started to work. I think there were polarity issues or something.
I had a switch that switched the power from Fiddle Yard road 2 into either road 2 or 3. However both Fiddle 2 and 3 were being powered regadless of the switch position. Indeed all 3 parts of the DTDP switch were live. I do not fully understand what is happening but this continues, and it is something to do with the point. Anyway, although I have yet to figure out exactyl what is going on, by converting the switch from switching between Road 2 or 3, to just Road 3 or off, it now works as planned.
The issue is that when power is sent from Fiddle 2 into Road 3 (solid line above) it also powers Fiddle 3 (dashed line).
It is something I've not understood along the way. The logic required for wiring and electrics is something I stuggle with.
It now works as planned, however. Operationally this means I can have a loco on every fiddle and road except for one to allow for movement. On Road 1 with its isolating section at the end I can have two locos. This means I can have 6 locos on the layout at once and still have movement. 6 is too many, 4 is a better number. Plenty of scope for movement, unless wagons are introduced, then it gets a bit tight!
Next is to have more of a play with the Class 150's and 153's (plus my new 121) which are the key units for the layout, plus see if a 158 2 car will fit. Then carry on with the scenery.