Can't sign Michelson PACK data with Signatory: "unknown tag 5" error

[TristanAllaire]

Hello,

I have been using the beta version of signatory (version 0.3.3-beta-rc1-amd64) as a remote signer on my Taquito dApp for the past couple years and everything worked fine with it.
In my dApp I use it to sign transaction but also to sign Michelson code (PACK).

In order to get the latest features, I decided to update Signatory to version 1.1.8. However now the signing of Michelson code does not work anymore and I get this error:

gotez: unknown tag 5

Here's a portion of the trace:

Overall it looks like I can only sign transactions with Signatory now and not Michelson code anymore (everything else seems to work on my dApp). I even tried the example listed here from the Taquito doc and I get the same issue. I tried using Magic bytes in the signing operation on Taquito but it doesn't fix anything.

Do you know how I could fix my issue?

Thank you and have a nice day.