After being visible for many weeks, today the title block became invisible and unprintable on Layout Page 3. As you will see in the video, the title block can be selected, and appears to have the same properties as the title block on other pages. The title block also disappeared from page 6, but I was able to reinsert it. Attempts to reinsert the title block on Page 3 do not overcome the visibility problem.
I upgraded from R4 to R6 in October 2018. I did not use title blocks before R6. I noticed an old posting with a similar problem in R5, but that was apparently fixed.I followed the suggestion of exploding the block, which resulted in 14 objects. After that, I was not able to see nor select those objects on Page 3. Subsequent attempts to reinsert the block on Page 3 were not successful. Blocks in layouts are invisible