[Next.js] Sourcemaps offset by 2 lines on Vercel

[lforst]

Description

Reported in https://discord.com/channels/621778831602221064/621778831602221072/1339278143286018181

[lforst]

I cannot reproduce this right now. Waiting for response on discord.

[mydea]

did we hear anything back here? Else, I think we can close this @lforst?