Click twice to advance to next month?

Each time my sites newly-load their calendar pages (using Time.ly calendar on two sites), clicking the button for the next month (in month view) doesn’t work; the same month stays displayed. Clicking the button a second time loads the next month, and from that point on single clicks navigate just fine. But if I close the tab or browser, and re-visit the site(s), the same behavior occurs again.

Both WordPress sites, both using a theme called “Parabola” by Cryout Creations. Both sites fully updated (core and plugins).

This odd navigation behavior has come up on occasion with the Time.ly calendar, then seems to get fixed (update, or fixes itself?!?), then re-occurs a month or two later. Any ideas?

https://wordpress.org/plugins/all-in-one-event-calendar/