There could be. It can be read as B has more influence on A than C does. It could also mean that B has more influence on A than it does on C. It might depend on what A, B and C are.

It is used to talk about what shapes the way things/people are. I'll give you an example: "Nowadays, what people think (A) is more influenced by social media (B) than newspaper articles (C)." means "What people think is a result of both social media and newspaper articles, but social media is more important." Is there any ambiguity in this type of sentence construction? Well, it doesn't state the exact amount of influence, or whether there's possibly other factors that influence the situation (maybe the opinions of friends and family have a greater influence on what people think? maybe the radio? maybe TV? maybe religion?) BUT what is not ambiguous is that the sentence claims social media is more important than newspapers.