Bota Theme Mobile Display Problem

Bota:

A web site I take care of uses the Bota theme:

sallybartonbowenwork.com

Clients have complained that they cannot access the site on a mobile phone.

On my Motorola, I can see the site and it works OK at first.
Then, if I touch the hamburger and select a page, I might get the page or I might get a 404 error.

When the latter happens, it seems to be that the url has this appended to it:

.html?m

So, of course, it gets a 404.

Other times, the display disintegrates into a bland, no-picture one.
Something I have not put into the theme.

Ideas?

:Susan Sailow