SUMMARY
The comic strip plasmoid seems to often get to a state where it is refreshing the comic in a busy loop.

STEPS TO REPRODUCE
1. Add a comic widget with at least two comics since this doesn't seem to reproduce with just one. (I'm using https://store.kde.org/p/2160754 and https://store.kde.org/p/1080452)
2. Switch between the comic tabs a few times. Possibly you also need to click "next" on the latest xkcd strip to trigger the bug. 
3. Observe the plasmashell logs: journalctl -f /usr/bin/plasmashell

OBSERVED RESULT
At some point, the comic widget will start updating xkcd in a busy loop several times a second:

Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Requesting image for comic 2943 from https://imgs.xkcd.com/comics/unsolved_chemistry_problems.png"
Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Received comic image data."
Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Requesting data for latest comic from https://xkcd.com/info.0.json"
Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Requesting data for latest comic from https://xkcd.com/info.0.json"
Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Received data from the XKCD API with ID 257"
Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Data parsed successfully: {\"month\": \"6\", \"num\": 2943, \"link\": \"\", \"year\": \"2024\", \"news\": \"\", \"safe_title\": \"Unsolved Chemistry Problems\", \"transcript\": \"\", \"alt\": \"I'm an H\\u207a denier, in that I refuse to consider loose protons to be real hydrogen, so I personally believe it stands for 'pretend'.\", \"img\": \"https://imgs.xkcd.com/comics/unsolved_chemistry_problems.png\", \"title\": \"Unsolved Chemistry Problems\", \"day\": \"7\"}"
Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Requesting data for requested comic 2942 from https://xkcd.com/2942/info.0.json"
Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Received data from the XKCD API with ID 256"
Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Data parsed successfully: {\"month\": \"6\", \"num\": 2942, \"link\": \"\", \"year\": \"2024\", \"news\": \"\", \"safe_title\": \"Fluid Speech\", \"transcript\": \"\", \"alt\": \"Thank you to linguist Gretchen McCulloch for teaching me about phonetic assimilation, and for teaching me that if you stand around in public reading texts from a linguist and murmuring example phrases to yourself, people will eventually ask if you're okay.\", \"img\": \"https://imgs.xkcd.com/comics/fluid_speech.png\", \"title\": \"Fluid Speech\", \"day\": \"5\"}"
Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Requesting image for comic 2942 from https://imgs.xkcd.com/comics/fluid_speech.png"
Jun 09 17:09:44 kuusnepa plasmashell[3686]: "Received data from the XKCD API with ID 257"
(etc.)

EXPECTED RESULT
Busy-looping should not happen.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 5.27.11
(available in About System)
KDE Plasma Version: 5.27.11
KDE Frameworks Version: 5.115.0
Qt Version: 5.15.10

ADDITIONAL INFORMATION