Shift error in grid – boxes are overlapping

Problem – grid items are overlapping one another and last item appears on top of the footer.
http://i.imgur.com/NGqrHkB.png

Unfortunately this occurs only on mobile browsers, co I can’t give screen with Inspect element or sth like that.

Here’s the configuration i used:
http://i.imgur.com/PlHP9jq.png
(In “Field Selection” – only “Title” is checked.)

You can see the grid here:
http://dentanis.test.lemisoft.pl/secret-test-site2/

How can I fix it? Thanks in advance for help. 🙂

https://ww.wp.xz.cn/plugins/the-post-grid/