It's everything that was printed in the Warnings buffer.

Actually, maybe it wasn't everything as I didn't scroll up in the buffer! It just happened again:

Warning (org-element): org-element--cache: Warning(scratch.org): Org parser error in scratch.org::8756. Resetting.

The error was: (error "Invalid search bound (wrong side of point)")
Backtrace:
nil
Please report this to Org mode mailing list (M-x org-submit-bug-report).
Backtrace:
org-element-cache diagnostics(scratch.org): Recovering persistent cached element: "(example-block (:standard-properties [1493 1504 nil nil 2027 0 nil nil element t nil nil nil nil #<buffer scratch.org> nil nil (section (:standard-properties [2 2 2 2027 2027 0 nil first-section element t nil 2 2027 nil #<buffer scratch.org> nil nil ...]))] :value [org-element-deferred org-element--unescape-substring (27 520) t] :switches nil :number-lines nil :preserve-indent nil :retain-labels t :use-labels t :label-fmt nil :results (\"\")))"
org-element-cache diagnostics(scratch.org): Recovering persistent cached element: "(src-block (:standard-properties [2 2 nil nil 1493 1 nil top-comment element t nil nil nil nil #<buffer scratch.org> nil nil (section (:standard-properties [2 2 2 2027 2027 0 nil first-section element t nil 2 2027 nil #<buffer scratch.org> nil nil ...]))] :language \"octave\" :switches nil :parameters \":results output :exports both\" :number-lines nil :preserve-indent nil :retain-labels t :use-labels t :label-fmt nil :value [org-element-deferred org-element--unescape-substring (49 1480) t]))"
org-element-cache diagnostics(scratch.org): Recovering persistent cached element: "(section (:standard-properties [2 2 2 2027 2027 0 nil first-section element t nil 2 2027 nil #<buffer scratch.org> nil nil (org-data (:standard-properties [1 1 2 2027 2027 0 nil org-data nil t nil 4 2027 nil #<buffer scratch.org> nil nil nil] :path \"/Home/ps/scratch.org\" :CATEGORY \"scratch\" :fragile-cache nil))]))"
org-element-cache diagnostics(scratch.org): Recovering persistent cached element: "(org-data (:standard-properties [1 1 2 2027 2027 0 nil org-data nil t nil 4 2027 nil #<buffer scratch.org> nil nil nil] :path \"/Home/ps/scratch.org\" :CATEGORY \"scratch\" :fragile-cache nil))"
org-element-cache diagnostics(scratch.org): Loading persistent cache for ~/scratch.org