I did as instructed.
Here is a couple of instances of what I saw in *Messages* right after I was able to trigger the problem.
case 1:
DBus-Event (dbus-event :post-blank 0 :post-affiliated 1455145 :mode nil :granularity element :cached t :parent (section (:begin 1179957 :end 1609350 :contents-begin 1179957 :contents-end 1609349 :robust-begin 1179957 :robust-end 1609347 :post-blank 1 :post-affiliated 1179957 :mode section :granularity element :cached t :parent (headline (:raw-value Old stuff :begin 1179945 :end 1609350 :pre-blank 0 :contents-begin 1179957 :contents-end 1609349 :robust-begin 1180109 :robust-end 1609347 :level 1 :priority nil :tags nil :todo-keyword nil :todo-type nil :post-blank 1 :footnote-section-p nil :archivedp nil :commentedp nil :post-affiliated 1179945 :ARCHIVE_TIME 2020-10-17 Sat 15:00 :ARCHIVE_FILE ~/work/
worklog.org :ARCHIVE_OLPATH Scratch :ARCHIVE_CATEGORY worklog :title Old stuff :mode nil :granularity element :cached t :parent (org-data (:begin 1 :contents-begin 1 :contents-end 15432855 :end 15432856 :robust-begin 3 :robust-end 15432853 :post-blank 1 :post-affiliated 1 :path /home/kun/work/worklog.org_archive :mode org-data :CATEGORY worklog :cached t :org-element--cache-sync-key nil)) :org-element--cache-sync-key nil)) :org-element--cache-sync-key nil)) :org-element--cache-sync-key nil) [2 times]
Entering debugger...
DBus-Event (dbus-event x . make4ht)
funcall-interactively: Wrong type argument: listp, "make4ht"
case 2:
DBus-Event (dbus-event :post-blank 0 :post-affiliated 1455145 :mode nil :granularity element :cached t :parent (section (:begin 1179957 :end 1609350 :contents-begin 1179957 :contents-end 1609349 :robust-begin 1179957 :robust-end 1609347 :post-blank 1 :post-affiliated 1179957 :mode section :granularity element :cached t :parent (headline (:raw-value Old stuff :begin 1179945 :end 1609350 :pre-blank 0 :contents-begin 1179957 :contents-end 1609349 :robust-begin 1180109 :robust-end 1609347 :level 1 :priority nil :tags nil :todo-keyword nil :todo-type nil :post-blank 1 :footnote-section-p nil :archivedp nil :commentedp nil :post-affiliated 1179945 :ARCHIVE_TIME 2020-10-17 Sat 15:00 :ARCHIVE_FILE ~/work/
worklog.org :ARCHIVE_OLPATH Scratch :ARCHIVE_CATEGORY worklog :title Old stuff :mode nil :granularity element :cached t :parent (org-data (:begin 1 :contents-begin 1 :contents-end 15432855 :end 15432856 :robust-begin 3 :robust-end 15432853 :post-blank 1 :post-affiliated 1 :path /home/kun/work/worklog.org_archive :mode org-data :CATEGORY worklog :cached t :org-element--cache-sync-key nil)) :org-element--cache-sync-key nil)) :org-element--cache-sync-key nil)) :org-element--cache-sync-key nil) [2 times]
dbus-event-bus-name: D-Bus error: "Not a valid D-Bus event", (dbus-event :post-blank 0 :post-affiliated 1455145 :mode nil :granularity element :cached ...)