Unfortunately Apple are experiencing ongoing issues with regards to podcast artwork. Specifically when artwork is updated within your Podcast.co account it is not reflected on Apple Podcasts. This issue is affecting all podcast hosts, not just Podcast.co.
Apple are aware of this issue and have informed us their teams are working on fixing it. Until then, this is the process for getting things updated.
If you submitted your own podcast to Apple or have access to it in PodcastsConnect:
Log into PodcastsConnect: https://podcastsconnect.apple.com
Open this page and scroll to the bottom and click Contact Our Support Team: https://podcasters.apple.com/support/
Fill in the contact form, selecting Podcast Not Updating for the Topic. Including the correct artwork for your podcast as an attachment can also help their team.
If Podcast.co submitted your podcast to Apple:
Contact us using the Support Chat bubble in the bottom right, or via email to [email protected]
Please include the name of the podcast who's artwork is appearing incorrectly.
We will reach out to Apple on your behalf and keep you updated on the process.
If another hosting platform submitted your podcast to Apple and you do not have access to it in PodcastsConnect:
Contact Apple Podcasts support directly via email at [email protected]
Let them know about the artwork issue, but also request a transfer. This way Apple can transfer the podcast into an account you create/own with them instead so you have access in the future.