At most one backlink shown in org-roam buffer, and it's not followable

Troubleshooting
1

(In case it’s relevant, here’s my .emacs config dotfile.)

I have the following four files:

~/org-roam/pers/20200923152005-next_meeting.org
~/org-roam/ofiscal/20201106093226-putting_tax_co_online.org
~/org-roam/tech/20210414195930-aws-frequently-used-commands.org
~/org-roam/ofiscal/20210419112845-tax_co_web_setting_up_an_ec2_instance_to_serve.org

The first three all refer to the last (the “many-parented” file). When, from the many-parented file, I run org-roam-buffer-toggle, the screen splits and the following error appears in the new window:

Debugger entered--Lisp error: (wrong-type-argument char-or-string-p (1 3096 ""))
  org-roam-fontify-like-in-org-mode((1 3096 ""))
  org-roam-node-insert-section(:source-node #s(org-roam-node :file "/home/jeff/org-roam/tech/20210414195930-aws-freque..." :file-hash nil :file-atime (24821 36310 999062 452000) :file-mtime (24821 34552 373659 352000) :id "b4493a4d-f640-43aa-9f7c-ef36c5371a03" :level 0 :point 1 :todo nil :priority nil :scheduled nil :deadline nil :title "AWS, frequently used commands" :properties (("CATEGORY" . "20210414195930-aws-frequently-used-commands") ("ID" . "b4493a4d-f640-43aa-9f7c-ef36c5371a03") ("BLOCKED" . "") ("FILE" . "/home/jeff/org-roam/tech/20210414195930-aws-freque...") ("PRIORITY" . "B")) :olp nil :tags nil :aliases nil :refs nil) :point 3096 :properties (:outline ("the commands")))
  org-roam-backlinks-section(#s(org-roam-node :file "/home/jeff/org-roam/ofiscal/20210419112845-tax_co_..." :file-hash nil :file-atime (24825 61126 938412 443000) :file-mtime (24825 61122 391445 495000) :id "dc3cf615-f76e-40ed-b20d-2ea09ba3f74b" :level 0 :point 1 :todo nil :priority nil :scheduled nil :deadline nil :title "deploy tax.co.web over EC2" :properties (("CATEGORY" . "20210419112845-tax_co_web_setting_up_an_ec2_instan...") ("ROAM_ALIASES" . "\"tax.co.web on EC2\"") ("ID" . "dc3cf615-f76e-40ed-b20d-2ea09ba3f74b") ("BLOCKED" . "") ("FILE" . "/home/jeff/org-roam/ofiscal/20210419112845-tax_co_...") ("PRIORITY" . "B")) :olp nil :tags nil :aliases ("tax.co.web on EC2") :refs nil))
  org-roam-buffer-persistent-redisplay()
  org-roam-buffer-toggle()
  funcall-interactively(org-roam-buffer-toggle)
  call-interactively(org-roam-buffer-toggle nil nil)
  command-execute(org-roam-buffer-toggle)

If I quit that buffer (by pressing “q”), the org-roam buffer replaces it. But it lists only the third file:

deploy tax.co.web over EC2
Backlinks:
AWS, frequently used commands (the commands)

And when I try to click on (or press enter with point at) the line AWS, frequently used commands (the commands), I get user-error: There is no thing at point that could be visited.