Hey @Peter_Smith - that is definitely odd. thanks for sharing the snippet screenshot there. Would you be willing to share your full extension code as a Zip/Archived file so that I can try to replicate on my end here and potentially get in touch with the POS extensibility product team on your behalf (we won’t share any code externally, just within Shopify)?
I can set up a DM on my end here to facilitate that if that works for you, since that might be a bit more private. Just ping me here and I can set that up right away so we can get the ball rolling and investigate further - hope to speak soon!