I can see this error in the browser console when filtering one of the topics:
Uncaught (in promise) TypeError: i is undefined
initialize initialize-discourse-post-badges.js:89
b formatter.js:395
b formatter.js:395
draw formatter.js:395
render formatter.js:395
o bookmark.js:114
exports bookmark.js:114
e category-tag.js:28
e category-tag.js:28
e category-tag.js:28
exports group.js:15
exports group.js:15
e upload.js:65
l upload.js:65
exports group.js:15
e upload.js:65
l upload.js:65
e upload.js:65
rerenderWidget mount-widget.js:43
invoke client-error-handler.js:88
flush client-error-handler.js:88
flush client-error-handler.js:88
_end client-error-handler.js:88
_boundAutorunEnd client-error-handler.js:88
promise callback*35311/r/< client-error-handler.js:88
flush bookmark.js:114
_scheduleAutorun client-error-handler.js:88
_end client-error-handler.js:88
_boundAutorunEnd client-error-handler.js:88
promise callback*35311/r/< client-error-handler.js:88
flush bookmark.js:114
_scheduleAutorun client-error-handler.js:88
_end client-error-handler.js:88
_boundAutorunEnd client-error-handler.js:88
promise callback*35311/r/< client-error-handler.js:88
flush bookmark.js:114
_scheduleAutorun client-error-handler.js:88
_end client-error-handler.js:88
_boundAutorunEnd client-error-handler.js:88
promise callback*35311/r/< client-error-handler.js:88
flush bookmark.js:114
_scheduleAutorun client-error-handler.js:88
_end client-error-handler.js:88
_boundAutorunEnd client-error-handler.js:88
promise callback*35311/r/< client-error-handler.js:88
flush bookmark.js:114
_scheduleAutorun client-error-handler.js:88
_ensureInstance client-error-handler.js:88
schedule client-error-handler.js:88
30408 hashtag-autocomplete.js:158
_ named-references.js:49
m named-references.js:49
g named-references.js:49
n named-references.js:49
promise callback*95743/m/</n< named-references.js:49
m named-references.js:49
invoke client-error-handler.js:88
flush client-error-handler.js:88
flush client-error-handler.js:88
_end client-error-handler.js:88
end client-error-handler.js:88
_run client-error-handler.js:88
run client-error-handler.js:88
d bookmark.js:114
initialize-discourse-post-badges.js:89:14
Looks like an issue with Post Badges?