org-capture-templates stopped working

Question

I have org-capture-templates defined as below and until today could capture and log my runs fine, but as of today they've stopped working...

(setq org-capture-templates
    '(;; Computing
        ("c" "Computing")
        ("ce" "Emacs" entry (file+olp "~/org/computing.org" "Emacs")
        "* TODO %t %?\n" :prepend t)
        ;; Exercise
        ("e" "Exercise")
        ("er" "Logging a run" table-line (file+olp "~/org/training/training.org" "Running" "Log")
            "| %t | %? | km | min + s | | |" :prepend t)
        ("ec" "Logging a cycle" table-line (file+olp "~/org/training/training.org" "Cycling" "Log")
            "| %t | %? | km | min + s | | |" :prepend t)))

Snippet of my ~/org/training/training.org is...

* Running
** Log
#+NAME: running-log
#+CAPTION: Running Log
| Date             | Route             | Distance | Time         | Pace                          | Notes       |
|------------------+-------------------+----------+--------------+-------------------------------+-------------|
| <2021-01-03 Fri> | Shorter 12km run  | 12.25km  | 60min + 25s  | 4 min / km + 55.918367 s / km | Less icey!        |
| <2021-01-01 Fri> | Longer 16km run   | 16.22km  | 80min + 03s  | 4 min / km + 56.115906 s / km | Icey!            |

...and ~/org/computing.org is...

* Emacs
** TODO <2020-11-11 Wed> vterm only on non-work computers.

If I C-c c to start org-capture and select [c]... Computing... [e] Emacs I'm prompted for an entry under * Emacs in computing.org and until today [e]... Exercise... [r] Logging a run brought up a blank template like...

| <2021-01-03 | <cursor here to start entry> | km | min + s | | |

...and I could enter details distance and time, save it and the entry appeared in the ~/org/training/training.org with the pace calculated.

Now though I'm informed...

Capture abort: Symbol's function definition is void: assert

Debugging shows...

Debugger entered--Lisp error: (error "Capture abort: Symbol’s function definition is voi...")
  signal(error ("Capture abort: Symbol’s function definition is voi..."))
  error("Capture abort: %s" "Symbol’s function definition is void: assert")
  org-capture(nil)
  funcall-interactively(org-capture nil)
  call-interactively(org-capture nil nil)
  command-execute(org-capture)

...which doesn't mean much to me. If I look at the entry under [C] Customize org-capture-templates I have...

[INS] [DEL] Choice: [Value Menu] Multikey description:
            Keys       : e
            Description: Exercise
[INS] [DEL] Choice: [Value Menu] Template entry:
            Keys           : er
            Description    : Logging a run
            Capture Type   : [Value Menu] Table line
            Target location: [Value Menu] File & Outline path:
            Filename       : [Value Menu] Literal: ~/org/training/training.org
            Outline path:
            [INS] [DEL] Headline: Running
            [INS] [DEL] Headline: Log
            [INS]
            Template       : [Value Menu] String: | %t | %? | km | min + s | | |
            Plist:
            [X] Key: :prepend t
            [ ] Key: :immediate-finish t
            [ ] Key: :jump-to-captured t
            [ ] Key: :empty-lines 1
            [ ] Key: :empty-lines-before 1
            [ ] Key: :empty-lines-after 1
            [ ] Key: :clock-in t
            [ ] Key: :clock-keep t
            [ ] Key: :clock-resume t
            [ ] Key: :time-prompt t
            [ ] Key: :tree-type week
            [ ] Key: :unnarrowed t
            [ ] Key: :table-line-pos String: 
            [ ] Key: :kill-buffer t
            [INS]

Which looks fine to my untrained eye. Reading the C-h v org-capture-templates (see also here, I don't see that anything has changed since I first wrote this.

I'm running GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.22) of 2020-11-29 (recent compile date is because its under Gentoo). I run Emacs as a daemon and connect a client to it and tried first re-evaluating my org-capture-template but with the same result. I then restarted the daemon and the error persisted.

I don't understand the debugging and why org-capture is being called interactively with nil nil arguments as I think I have defined the templates correctly and it worked fine until today. Any insight would be gratefully received.

EDIT (2021-01-03) :

After adding (require 'cl) as suggested it still errors with the following backtrace...

Debugger entered--Lisp error: (error "Capture abort: Invalid function: assert")
  signal(error ("Capture abort: Invalid function: assert"))
  error("Capture abort: %s" "Invalid function: assert")
  org-capture(nil)
  funcall-interactively(org-capture nil)
  call-interactively(org-capture nil nil)
  command-execute(org-capture)

EDIT (2020-01-04) :

I found things still worked on a laptop, but then updated packages and org-capture broke in the same way there. The packages updated don't seem related to org but I'm detailing them here for reference...

company-20201214.1620
ein-20201217.1508
flycheck-20201214.2154
forge-20201212.905
magit-20201212.929
org-ref-20201126.1924
pass-20190830.2017
projectile-20201214.839
python-mode-20201218.751
pyvenv-20201210.1509
auctex-12.3.1
dash-20201215.59
dash-functional-20201215.40
ess-20201217.1440
git-commit-20201115.2313
helm-20201215.1623
helm-core-20201202.907
ivy-20201217.1559
key-chord-20160227.1238
markdown-mode-20201211.329
mpdel-20201026.1123
transient-20201205.1610