Enable search feature breaks member directory

When I create a new member directory with default settings and use its shortcode on a page ‘Members’, the results display fine (I get a list of registered members).

If I edit the member directory and select ‘Enable Search Feature’ and in ‘Choose field(s) to enable in search’ I add ‘Last name’, the ‘Members’ page allows me to search by last name. However, when I search for a valid last name, it tells me ‘1 member’ has been found, and the results are generated, but are not visible. What I mean by that is there’s a big white space appears where the results should be, and when I right click -> Inspect in chrome I can see the div ‘um-members masonry’, ‘um-member card’, ‘um-member name’ etc. are present, but the results are invisible and all I can see is the background colour of my page.

If I then disable ‘Enable search feature’ (i.e. return to the default settings), on my Members page the results are generated, but invisible. It’s as if they have been hidden by an overlaying blank div (um-form?) which matches my background.

Thanks in advance for any help!