An update. I cloned the website and checked all the unchecked template updates. Nothing special happened and I proceeded with updating Helix Ultimate from 2.0.6 to 2.0.7. Again, all went well.
I then proceeded with updating SP builder from 3.8.2 to 3.8.3 and the issue with the Gazette specific add-ons (Articles Slides and Articles Vertical slider), reappeared, as seen before on the production site. See image in the hidden section.
As expected, I got console errors on the owl and jquerymin.js files as follows.
OWL.MIN.JS ERRORS
12owl.carousel.min.js:1
Uncaught TypeError: Cannot read properties of undefined (reading 'clone')
at e.run (owl.carousel.min.js:1:3005)
at Object.i [as run] (jquery.min.js?3.6.0:2:88757)
at e.update (owl.carousel.min.js:1:7517)
at e.<anonymous> (owl.carousel.min.js:1:17549)
at i (jquery.min.js?3.6.0:2:88757)
9owl.carousel.min.js:1
Uncaught TypeError: Cannot read properties of undefined (reading 'clone')
at e.run (owl.carousel.min.js:1:3005)
at Object.i [as run] (jquery.min.js?3.6.0:2:88757)
at e.update (owl.carousel.min.js:1:7517)
at e.<anonymous> (owl.carousel.min.js:1:17549)
at i (jquery.min.js?3.6.0:2:88757)
JQUERY.MIN.JS ERRORS
jquery.min.js?3.6.0:2
Uncaught TypeError: a(...).find(...).andSelf is not a function
at c.<anonymous> (owl.carousel.min.js:2:7592)
at HTMLDivElement.i (jquery.min.js?3.6.0:2:88757)
at HTMLDivElement.dispatch (jquery.min.js?3.6.0:2:43064)
at HTMLDivElement.v.handle (jquery.min.js?3.6.0:2:41048)
at Object.trigger (jquery.min.js?3.6.0:2:71515)
at HTMLDivElement.<anonymous> (jquery.min.js?3.6.0:2:72110)
at Function.each (jquery.min.js?3.6.0:2:3003)
at S.fn.init.each (jquery.min.js?3.6.0:2:1481)
at S.fn.init.trigger (jquery.min.js?3.6.0:2:72086)
at e.trigger (owl.carousel.min.js:1:22366)
It seems that the new SP builder version messes up these files somehow. That is where my technical grasp of the matter ends.
Please, provide an answer and a fix ASAP.
Thank you