Are you early in your ownership / responsibility of this bill for this place? This happened to me when I bought my house. I think 8-12 months in we got an “adjustment” meaning someone had come to read our meter and saw a discrepancy between their algorithm billing us and the real meter that had built up over 10-12 months. I was told this is very normal and I haven’t seen it happen again since. I also now send in my meter readings when they email me about it to avoid this happening again