Large drop in percentile weight experiences at 10 months

Son had his 10mo health visitor review. He's tracking ahead developmentally but weight wise he's in the 5th percentile. He was tracking consistently on the 50th percentile 2 months ago and has had a huge drop. He has started crawling in that time though and is a very very active baby so I am not concerned and neither was the HV, but she has advised to get him weighed again in a month to check there's no further drops. My question is, has anyone else experienced such a drop and can he catch up and get back on track weight wise or is he likely to be small forever now?