Epub - incorrect spaces between some paras on export

Hi I have created a reflowable epub in InDesign. I have applied styles throughout. In screenshot 1 below, you will see two paras with my indent para style applied. But on export, a space appears between the two paras. Screenshot 2 is the Thorium reader view where you will see the space. .It happens here and there throughout the document.

This is the first time this has happened to me and I can’t find any logic to it.  In the para style, there is no space before or space after. I show hidden characters in screenshot 1, which is the same hidden character I see for the other indent paras that export fine.

When I try to fix the problem eg make the 2 paras one para, new spaces appear between other unrelated paras throughout the document. I have been exporting epubs for months without this happening and have not changed the export settings so that can’t be a factor.  It is also nothing to do with reflowability as I have not had this problem before in months with my reflowable epubs on any e-reader.

Screenshot: Inside InDesign

Screenshot: Thorium e-reader