Help: writing on mindmap vanishes - SOLVED user error

Hello all,
I am full of questions lately as I come to terms with MN4.
Yesterday I was working on the iPad with no problems encountered. Today I opened the same studyset and everything I try to hand-write on the mindmap (a) vanishes in a few seconds (“vanish mode” is not enabled anywhere - have never used this); and (b) lays down like a lilac marker, which I have never set up. Trying to change to a regular pen/pencil does nothing. Mindmap writing is enabled, of course. Writing on the document is fine.

Hoping you can help as I am at my wits’ end! If I invoked a setting change I am not aware of it. It seems like something “vanish mode” would look like, but I do not see this enabled anywhere.

ETA: never mind - I figured it out. This behavior was the result of “Mindmap Gesture” being turned on. I have never used this, and did not turn it on intentionally, so did not recognize the color/behavior. Decided to leave my message here in the Forum in case other new users encounter this and waste several hours trying to figure it out.