Is this offensive

So me and my husband run a small business, the majority of our customers are Hispanic and many don’t speak English. Me and my husband are white but have become pretty fluent in Spanish so we can communicate with our customers without needing a translator.

One day a customers came in and she appeared to be Hispanic and my husband went up to greet her and was speaking Spanish. The women then says “I am not spanish and a lot of people would be offended that you assume they are”.

In your opinion was this offensive? All my husband did was greet her in Spanish and never stated he thought she was Hispanic.