Nasty experience with LibreOffice Writer 5.1.2.2

I keep my Linux notes as a Writer document. The files is about 29 pages long (33.3 KiB).

I had no problems with an earlier version of LibreOffice Writer, but with the current version from the software center in 16.04, whenever I opened this file, my laptop's temperature and CPU usage shot up to 60 degrees Celsius and 60% and stayed there for about 2-3 min. The program was unusable during this time. After things cooled down it was usable: I could enter text or highlight stuff.

After several tries, I noticed that the pages shown in the left coer of the status bar decreased to just one during the madness. I then saw that I had Web rather than Normal selected in the View menu. This never caused problems previously. Switching to Normal fixed things. I don't know why.