I would have thought so too, but Megs is pretty clear about 'mingling' Sparks and Primal takes OPs spark into his own Spark chamber...until his body finishes upgrading anyway.
It's quite possible (albeit just more fanwank/conjecture) that the sparks of OP and Megs (being both 'guzzler' sparks and exceptionally powerful ones at that) mingle initially until their host bodies are capable of holding them and then return to being separate once it's 'safe' to do so.Again, my first thoughts are the same as yours, but the TMs do apparently have a little bit of organic matter in robot mode - even if it is mostly chest musculature.
Nice...that provides a decent explanation. When the not-quite cloning device explodes in Feral Scream part 1 Megs is present but Optimus isn't. After the Transwarp wave energy having an effect on existing- and protoform-Transformers (at least Predacons and Maximals) that works re. 'infecting' Megs, albeit on a cloning-machine VS Planet-Buster scale.
I salute thee sirrah.![]()