Two-tone Warner's Safe Kidney & Liver Cure bottle?

[flyingfrog2015]

Hello. I don't know if I have something unusual here or not. I've never seen any Warner's Safe bottles that appear to be two-tone until now. The left 2/3 of my most recently acquired one looks amber whereas the right 1/3 looks honey amber, regardless of the lighting condition. I only have one other, and it looks uniformly amber, but I have seen hundreds of pictures of these bottles online and several at bottle shows, but I've never seen anything remotely like this. Are Warner's Safe bottles known to have color variation within the bottle like this or do I have something extremely rare? Thanks in advance!

 

[Semar]

Could it be that the glass is not evenly distributed in the mold?

 

[flyingfrog2015]

I guess that's a possible explanation, thanks!