Dear Jochen,
I have switched to a full network reset with ResetKernel(), and it WORKS like a charm!!! Not only that but now I was able to approximately reproduce ALL plots in the famous figure from Izhikevich's paper!! GREAT!!! Now, I will set out to implement my original target, the paper by Chen and Campbell:
Chen, L., Campbell, S.A. Exact mean-field models for spiking neural networks with adaptation. J Comput Neurosci 50, 445–469 (2022). https://doi.org/10.1007/s10827-022-00825-9
Thank you very much for all your invaluable help!!! cheers gus.-