Good morning/afternoon/evening!

A few days ago I took quite a long relaxing walk and returned to the house with no weakness in my leg muscles at all - YET I did notice sudden severe fatiguing of the deltoid muscles and some milder bulbar weakness which lasted for quite a few hours.

I remembered then that I wasn´t clear on a few points. Can anyone say which of the following are assumed to be correct?

1) Mary Walker phenomenon happens in a lot of autoimmune diseases
2) This phenomenon is pretty much exclusive to MG
3) Most MG patients experience this
4) Only some MG patients experience this

Thanks,

Anacrusis