Definitely NOT a pro but, as a person that tends to find DIY ways to resolve problems, this is very likely what I'd do:

Use JBWeld to seal any actual cracks in the metal flashing that may have the potential to be the beginning of a leak and then use Bondo -- yes, the auto repair stuff that withstands all kinds of weather (including 80+mph "winds" down the freeway) -- to smooth it and seal it from the weather ... then paint it to match the metal roof.

Thank you suezbell for your suggestion.

Something like this please.

Thanks Joseph, just very concerned about UV and longevity. Client wants it to last longer than 30 years........ Cost isn't the issue, so do you think copper trumps EPDM? Maybe that stuff or torchon under sheet copper? Metal fillets?

If cost isn't an issue, tear it off and use a proper detail. If not, use uncured EPDM.