disappearing image and text

I just installed this theme “simplus-blog” on my wordpress local test system. My current theme which I have activated is twentysixteen.

I have 2 posts to look at on my test system. The first post consists of an image followed by some test. The second post is a quote followed by some text. When I look at the source code for the page, it does display code to show the image and the text for the first post and it does show code to display the quote and the text for the second post.

After I activate “simplus blog”, the code to display the image is gone for the first post and no image shows up when you view the page, and, more strange, the code for the second post shows as a continuous stream of text. wordpress has dropped the code to display the quote and combined the two text paragraphs into one. the code to display the first part as a quote has disappeared.

I am seeing this in each case by using a right click and viewing the page source code. Something somewhere along the line has bypassed code that should be used to display info on my page. Both posts have been created using gutenberg.

if I re-activate twentysixteen, all returns to normal and the posts can be viewed as they were designed.

what is happening? and why is this occurring?

Al