Console errors

With this plugin enabled (and at version 3.3.8) I am getting the following errors in the console and JS on the page is breaking. Any ideas? Thanks!

jQuery.Deferred exception: this.$widget.gs_isotope is not a function TypeError: this.$widget.gs_isotope is not a function
at GS_Testimonial_filter_by.initIsotope (https://summitfundraising.co.uk/wp-content/plugins/gs-testimonial/assets/js/public.min.js?ver=3.3.8:375:42)
at new GS_Testimonial_filter_by (https://summitfundraising.co.uk/wp-content/plugins/gs-testimonial/assets/js/public.min.js?ver=3.3.8:355:12)
at ce.gs_testimonial_filter_by (https://summitfundraising.co.uk/wp-content/plugins/gs-testimonial/assets/js/public.min.js?ver=3.3.8:421:14)
at HTMLDivElement. (https://summitfundraising.co.uk/wp-content/plugins/gs-testimonial/assets/js/public.min.js?ver=3.3.8:434:16)
at ce.each (https://summitfundraising.co.uk/wp-includes/js/jquery/jquery.min.js?ver=3.7.1:2:3129)
at ce.each (https://summitfundraising.co.uk/wp-includes/js/jquery/jquery.min.js?ver=3.7.1:2:1594)
at gs_testimonial_do_filter_by (https://summitfundraising.co.uk/wp-content/plugins/gs-testimonial/assets/js/public.min.js?ver=3.3.8:433:25)
at gs_testimonial_widget_single_init (https://summitfundraising.co.uk/wp-content/plugins/gs-testimonial/assets/js/public.min.js?ver=3.3.8:457:4)
at HTMLDivElement. (https://summitfundraising.co.uk/wp-content/plugins/gs-testimonial/assets/js/public.min.js?ver=3.3.8:491:4)
at ce.each (https://summitfundraising.co.uk/wp-includes/js/jquery/jquery.min.js?ver=3.7.1:2:3129) undefined
(anonymous) @ jquery.min.js?ver=3.7.1:2
(anonymous) @ jquery.min.js?ver=3.7.1:2

jquery.min.js?ver=3.7.1:2 Uncaught TypeError: this.$widget.gs_isotope is not a function
at GS_Testimonial_filter_by.initIsotope (public.min.js?ver=3.3.8:375:42)
at new GS_Testimonial_filter_by (public.min.js?ver=3.3.8:355:12)
at ce.gs_testimonial_filter_by (public.min.js?ver=3.3.8:421:14)
at HTMLDivElement. (public.min.js?ver=3.3.8:434:16)
at ce.each (jquery.min.js?ver=3.7.1:2:3129)
at ce.each (jquery.min.js?ver=3.7.1:2:1594)
at gs_testimonial_do_filter_by (public.min.js?ver=3.3.8:433:25)
at gs_testimonial_widget_single_init (public.min.js?ver=3.3.8:457:4)
at HTMLDivElement. (public.min.js?ver=3.3.8:491:4)
at ce.each (jquery.min.js?ver=3.7.1:2:3129)
(anonymous) @ public.min.js?ver=3.3.8:375
GS_Testimonial_filter_by @ public.min.js?ver=3.3.8:355
(anonymous) @ public.min.js?ver=3.3.8:421
(anonymous) @ public.min.js?ver=3.3.8:434
each @ jquery.min.js?ver=3.7.1:2
each @ jquery.min.js?ver=3.7.1:2
gs_testimonial_do_filter_by @ public.min.js?ver=3.3.8:433
gs_testimonial_widget_single_init @ public.min.js?ver=3.3.8:457
(anonymous) @ public.min.js?ver=3.3.8:491
each @ jquery.min.js?ver=3.7.1:2
each @ jquery.min.js?ver=3.7.1:2
(anonymous) @ public.min.js?ver=3.3.8:481
(anonymous) @ public.min.js?ver=3.3.8:501
e @ jquery.min.js?ver=3.7.1:2
(anonymous) @ jquery.min.js?ver=3.7.1:2

public.min.js?ver=3.3.8:375 Uncaught TypeError: this.$widget.gs_isotope is not a function
at GS_Testimonial_filter_by.initIsotope (public.min.js?ver=3.3.8:375:42)
at new GS_Testimonial_filter_by (public.min.js?ver=3.3.8:355:12)
at ce.gs_testimonial_filter_by (public.min.js?ver=3.3.8:421:14)
at HTMLDivElement. (public.min.js?ver=3.3.8:434:16)
at ce.each (jquery.min.js?ver=3.7.1:2:3129)
at ce.each (jquery.min.js?ver=3.7.1:2:1594)
at gs_testimonial_do_filter_by (public.min.js?ver=3.3.8:433:25)
at gs_testimonial_widget_single_init (public.min.js?ver=3.3.8:457:4)
at HTMLDivElement. (public.min.js?ver=3.3.8:491:4)
at ce.each (jquery.min.js?ver=3.7.1:2:3129)
(anonymous) @ public.min.js?ver=3.3.8:375
GS_Testimonial_filter_by @ public.min.js?ver=3.3.8:355
(anonymous) @ public.min.js?ver=3.3.8:421
(anonymous) @ public.min.js?ver=3.3.8:434
each @ jquery.min.js?ver=3.7.1:2
each @ jquery.min.js?ver=3.7.1:2
gs_testimonial_do_filter_by @ public.min.js?ver=3.3.8:433
gs_testimonial_widget_single_init @ public.min.js?ver=3.3.8:457
(anonymous) @ public.min.js?ver=3.3.8:491
each @ jquery.min.js?ver=3.7.1:2
each @ jquery.min.js?ver=3.7.1:2
(anonymous) @ public.min.js?ver=3.3.8:481
(anonymous) @ public.min.js?ver=3.3.8:516
dispatch @ jquery.min.js?ver=3.7.1:2
ce.event.add.v.handle @ jquery.min.js?ver=3.7.1:2

public.min.js?ver=3.3.8:375 Uncaught TypeError: this.$widget.gs_isotope is not a function
at GS_Testimonial_filter_by.initIsotope (public.min.js?ver=3.3.8:375:42)
at new GS_Testimonial_filter_by (public.min.js?ver=3.3.8:355:12)
at ce.gs_testimonial_filter_by (public.min.js?ver=3.3.8:421:14)
at HTMLDivElement. (public.min.js?ver=3.3.8:434:16)
at ce.each (jquery.min.js?ver=3.7.1:2:3129)
at ce.each (jquery.min.js?ver=3.7.1:2:1594)
at gs_testimonial_do_filter_by (public.min.js?ver=3.3.8:433:25)
at gs_testimonial_widget_single_init (public.min.js?ver=3.3.8:457:4)
at HTMLDivElement. (public.min.js?ver=3.3.8:491:4)
at ce.each (jquery.min.js?ver=3.7.1:2:3129)

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