Error: Unknow signature subpacket: 10 ( and 100)

Hi all,
I'm using a private key exported by pgp desktop client, which I want to decrypt an email (or files atthaced) but, when I invoke the method "decryptMessageArmored" I show the error message in the object.

I'm working with objective-c project that use "kbpgp-2.0.9.js" library.

I analyzed the private key and I debugged the JS, and I found follow information usefully:
- the "unknow signature subpacket:10" is caused by [ subpacketType:"Placeholder for backward compatibility (0xa)" ]. this placehoder type is not present on the list of subpacket type supported in the library, but this valure is present the standard rfc4880
- the "unknow signature subpacket:100" is caused by Signature Packet with [ publicKeyAlgorithm: "undefined (0x64)" ] and [ subpacketType:"undefined (0x64)" ].

I cannot remove this value from key. I tried to ignore these errors on JS but the decryt method returns "Empty" as data value...

How I can decrypt files using key not generate by keybase?

I tried also to export this key using some pgp tools, but in all cases the Placeholder and the Undefined value is present...

Start with kbpgp-2.0.9.js and the decryptMessageArmored call, then compare handling of signature subpackets 10 and 100 with RFC 4880 and the exported private key. Reproduce the failure with the supplied key and determine whether successful decryption can be restored without dropping required packet data.

Written by the indexing model from the issue text.