Help with Pipelines error: "Unknown format code 'f' for object of type 'str'"

I'm getting an error on a pipeline. Any idea how to resolve this and what the specific issue is? 

Validation error: Incorrect template "The AP Program has changed from <b style='color:#f00;'>{{a.$prev.seo_program_name}}</b> ({{"${:,.2f}".format(a.$prev.quickbooks_invoice_grand_total)}}) to <b style='color:#00691c;'>{{a.seo_program_name}}</b> ({{"${:,.2f}".format(a.quickbooks_invoice_grand_total)}}). This is a cost difference of {{"${:,.2f}".format(a.quickbooks_invoice_grand_total-a.$prev.quickbooks_invoice_grand_total)}} ({{'%0.1f'| format(((a.quickbooks_invoice_grand_total-a.$prev.quickbooks_invoice_grand_total)/a.$prev.quickbooks_invoice_grand_total)*100|float)}}%)". ValueError: Unknown format code 'f' for object of type 'str'

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Matt Makris
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