In the styles drop-down box, at the bottom, there is a pair of right and left arrows to select the previous or next style of the same type. In my document, I had just made an H2 style paragraph and pressed return which moved the cursor down a line ready to start a text body style paragraph.
I clicked the right arrow thinking it could take me to the next H2 heading in a later document in the manuscript. Scrivener crashed.
I restarted Scrivener and repeated the above several times. Sometimes I used the right arrow (for next) and sometimes the left arrow (for previous). About 1 in 2 times, Scrivener crashed.
I tried the same with text body style selected and sometimes the whole text above the cursor was highlighted (including an H1 paragraph) which it seems to me has been noted elsewhere in this forum. After about a dozen attempts, Scrivener crashed even with text body style.
I am not sure, but the H2 style may have been one I created using this dialogue box but I’m pretty sure text body is a native style, all I have done is set the font to Liberation Serif 12.