I have tried reproducing it with a minimal example, and this seems to work for me:
* FOO
** TODO baz1
SCHEDULED: <2020-08-16 Sun>
some text
* BAR
** TODO baz2
SCHEDULED: <2020-08-16 Sun>
*** DONE baz3
SCHEDULED: <2020-08-16 Sun>
*** TODO baz4
SCHEDULED: <2020-08-16 Sun>
When in the agenda, on the front line of item baz, setting it to DONE state works fine.
OTOH, when going to the end of the line on the item baz, trying to set it to DONE results in the error message:
TODO state change from TODO to DONE blocked (by "TODO baz4")
Also, I have (org-enforce-todo-dependencies t), which causes the blocking, and (org-agenda-dim-blocked-tasks (quote invisible)), which hides baz2 from the agenda... because of this baz1 is followed directly by baz4 in my agenda window.
Just for completeness, this my lengthy org configuration:
(use-package org
:init
(defun org-archive-done-tasks ()
"Archive all DONE and CANCELED tasks in the subtree of the current entry"
(interactive)
(org-map-entries
(lambda ()
(org-archive-subtree)
(setq org-map-continue-from (outline-previous-heading)))
"//DONE|CANCELED" 'agenda))
:bind
(("C-c a" . org-agenda)
("C-c k" . org-capture)
:map org-mode-map
("C-c H" . org-archive-done-tasks)
("C-c e" . org-babel-execute-src-block))
:hook
(text-mode . visual-line-mode)
:config
(custom-set-variables
'(org-agenda-span 'day)
'(org-startup-indented t)
'(org-startup-folded nil)
'(org-directory "~/Workspace/org/")
'(org-agenda-files (list org-directory))
'(org-archive-location "archives.org::datetree/* %s")
'(org-agenda-diary-file (concat org-directory "diary.org"))
'(org-agenda-include-diary t)
'(org-deadline-warning-days 7)
'(org-agenda-skip-deadline-prewarning-if-scheduled 'pre-scheduled)
'(org-agenda-skip-scheduled-if-deadline-is-shown t)
'(org-agenda-skip-scheduled-if-done t)
'(org-agenda-todo-ignore-scheduled 'future)
'(org-agenda-tags-todo-honor-ignore-options t)
;; set SCHEDULED and DEADLINE leaders in agenda view
'(org-agenda-deadline-leaders (quote ("Deadline! " "In %d days: " "Late %d days: ")))
'(org-agenda-scheduled-leaders (quote ("Scheduled! " "For %d days: ")))
'(org-agenda-window-setup 'only-window)
'(org-todo-keywords
(quote ((sequence "TODO(t!)" "ONGOING(o!)" "WAITING(w@)" "|" "DONE(d@)" "CANCELED(c@)"))))
'(org-todo-keyword-faces
(quote (("WAITING" . "purple")
("ONGOING" . "orange")
("CANCELED" . "firebrick"))))
;; set ARCHIVE tag when todo state is set to CANCELED, and remove when reset to TODO
`(org-todo-state-tags-triggers
(quote
((todo . ((,org-archive-tag . nil)))
("CANCELED" . ((,org-archive-tag . t))))))
'(org-tag-persistent-alist
'(("TARGET" . ?t)))
'(org-tags-exclude-from-inheritance (quote ("TARGET")))
;; REFILE BEHAVIOUR
'(org-refile-targets
'((nil . (:level . 1))
(nil . (:tag . "TARGET"))))
'(org-refile-use-outline-path t)
'(org-goto-interface 'outline-path-completion)
'(org-outline-path-complete-in-steps t)
;; prefer in-steps that ido for refile completion
;; '(org-completion-use-ido t)
'(org-reverse-note-order t)
;; LOGGING
;; todo state changes should be logged into drawer
'(org-log-into-drawer t)
;; log when schedule or deadline changes
'(org-log-redeadline (quote time))
'(org-log-reschedule (quote time))
;;'(org-log-refile (quote time)) ; logs even when refiled during capture
;; PRIORITIES
'(org-priority-start-cycle-with-default t)
'(org-default-priority 70)
'(org-lowest-priority 70)
'(org-highest-priority 65)
'(org-agenda-sorting-strategy
'((agenda time-up todo-state-down priority-down)
(todo category-up priority-down)
(tags category-up priority-down)
(search category-up)))
;; DEPENDENCIES
'(org-enforce-todo-dependencies t)
'(org-enforce-todo-checkbox-dependencies t)
'(org-agenda-dim-blocked-tasks (quote invisible))
;; CUSTOM COMMANDS
'(org-agenda-custom-commands
'(("c" . "Custom commands")
("cb" "Backlog (tasks not scheduled)" todo "TODO"
((org-agenda-skip-function
'(org-agenda-skip-entry-if 'scheduled))))
("cc" . "Filter tasks by CATEGORY")
("cci" "INBOX tasks"
((alltodo ""))
((org-agenda-category-filter-preset '("+INBOX"))))
("ccf" "INFRA tasks"
((alltodo ""))
((org-agenda-category-filter-preset '("+INFRA"))))
("ccr" "ROLES tasks"
((alltodo ""))
((org-agenda-category-filter-preset '("+ROLES"))))))
;; CAPTURE TEMPLATES
'(org-capture-templates
(quote
(("t" "Task")
("tt" "Task (Scheduled)" entry
(file+headline "tasks.org" "INBOX")
"* TODO %^{Title}\nSCHEDULED: %t\n%?")
("td" "Task (Scheduled, with Deadline)" entry
(file+headline "tasks.org" "INBOX")
"* TODO %^{Title}\nSCHEDULED: %^{Schedule}t DEADLINE: %^{Deadline}t\n%?")
("e" "Event")
("et" "Event (with single datetime)" entry
(file+headline "events.org" "INBOX")
"* %^{Title}\n%^T\n%?")
("er" "Event (with date range)" entry
(file+headline "events.org" "INBOX")
"* %^{Title}\n%^t--%^t\n%?")
("m" "Memo" entry
(file+headline "memo.org" "INBOX")
"* %?\n%T\n")
("x" "Example" entry
(file+headline "example.org" "INBOX")
"* %?\n%^t\n"))))))
Regards,
Daniel