Double space in Amazon Kindle

Hello, first time here. I’ve just completed my book and submitted it to Amazon for distribution as an e-book. For some unknown reason, several chapters in the e-book have double spacing, while other’s are single spaced as I intended. When compiling, all the chapters are set in the single space. It looks correct on my end but keeps coming up when downloaded to my Kindle with those pesky double spaces. Help please.