Was originally going to make an issue for this but I ended up fixing it in the process. Original text detailing the bug below:

I think I've run into a bug with the output file when using dynamic patches. Here's one I wrote for the INFINITAS launcher:

{
    type: 'dynamic',
    name: 'Bypass Game File Validation',
    tooltip: 'Ignore expected SHA-256 from server, allowing the game to launch with a modified executable',
    patches: [
        {
            off: [0x74, 'XX', 0xB9, 'XX', 'XX', 'XX', 'XX', 0xE8, 'XX', 'XX', 'XX', 'XX', 0x48, 0x8B, 0x7D],
            on: [0xEB, 'XX', 0xB9, 'XX', 'XX', 'XX', 'XX', 0xE8, 'XX', 'XX', 'XX', 'XX', 0x48, 0x8B, 0x7D],
        },
    ],
},

I'm only replacing the first byte, so the rest is just there to make it sufficiently unique. I kept the wildcards in the on patch as XX assuming it would only change the first byte and leave the rest untouched.

After enabling the patch and saving the file, the output was a little different to what I expected.

It seems like the wildcard bytes are getting replaced with 00 instead of the original contents: