The only explaination for your Lambda affecting starting was that it had suffered a mechanical failure resulting in 'odd' voltage readings being sent to the Motronic.
In normal use the Lambda has no part in the start-up procedure,hence understandable doubt with your findings.
Reading all the questions raised with injection issues,it is becoming worrying that so few owners understand how their bike functions,(comment not addressed to you,Steptoe),and how few 'technicians' can give a 100% account of each component's function.
I admit when I first bought my GS,the injection was new to me,a trip to the dealers showed that I was wasting my time asking anything more complicated than 'so the spark plug ignites the mixture'.
Fortunately,a friend of a friend designs injection systems so everything was explained very clearly,but the lack of knowledge shown makes you concerned about the 'well,I did this and it worked,try it' ideas.