indenting first line causes wierd layout

I'm writing a lengthy book, and randomly on page 160, when I tab to indent a new paragraph and begin typing, I get a weird reaction from Pages. The first words I type in move to the left of the cursor - as they would if I were typing with an alignment se to the right of the page (I am working with a Justified alignment). Then, once the words fill in the tabbed space I started with, the words/cursor begins moving to the right as normal.

Ok, so you'd think the fix would be to go back and tab again at the beginning of the paragraph. When I do that, I have to tab 2x to get the cursor to move to the right. The cursor ends up in the correct spot, but the paragraph starts another tab over - there is a tabbed space to the left and to the right of my cursor, then the words begin.

Ok, so then I delete the extra tabbed space to the right of the cursor. This moves the cursor AND the paragraph back to the left side of the page, with no tabbed space at all. Now when I tab yet again, the tabbed space is twice the normal size - the cursor and paragraph are now double the space to the right as a single tab ought to go. I can backspace and tab as many times as I want now because this is the new normal.

I have made no changes to the tabs, or previous settings I've been working with so far in the book. I don't understand why this changed randomly, and have no idea how to fix it. I appreciate any ideas!