DRL's - One not as bright?

[ybeandy]

I have a pair of these (not necessarily these exact model)

https://www.amazon.co.uk/Transporter-Daytime-Running-Lights-Upgrade/dp/B08BXWZ2JN/ref=asc_df_B08BXWZ2JN/?tag=googshopuk-21&linkCode=df0&hvadid=431042856959&hvpos=&hvnetw=g&hvrand=3483359838909576497&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006953&hvtargid=pla-928881468187&psc=1&tag=&ref=&adgrpid=102658917240&hvpone=&hvptwo=&hvadid=431042856959&hvpos=&hvnetw=g&hvrand=3483359838909576497&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1006953&hvtargid=pla-928881468187

and today noticed that the OS one isn't dimmed, it is still on and working so I know it is not the fuse but it is 80% dimmer than the NS.

before I replace what do you guys suggest as the first port of call?