Once you've attached a banner to a sign, the banner image isn't displayed correctly. Currently, this is the case on the Switch Bedrock 1.21.92 Edition, but it's been like this since previous versions. Attached you'll find a picture of the banner and the banner on the shield.
MCPE-223549
Gafig bug at Shielde
Resolved
Duplicate
0
This issue is being tracked at MCPE-169640.