Files created in Libre office and converted to word slip up or down the page and dont remain stable.
Yes, as you have discovered, saving files in a non-native format can result in loss of formatting. Always save your files in LO’s native format. For Writer, that is .odt. When you need to share a file with someone who does not use LO, then (and only then) you can Export (not Save) the file in another format, for example, the proprietary Word format.
See here why: [Tutorial] Differences between Microsoft and AOO/LO files. Welcome to the vendor lock-in policy.
Nonetheless, simple documents are pretty consistent in both formats, it all depends on the complexity of the layout.
The main reason for this shift in formatting is the difference in page geometry definition coupled with the use of direct formatting.
In Writer, margins are no-print area and header/footer are taken out of the remaining area. In Word, margins defined the main text area and header/footer are positioned inside the margin. At first look, area available for discourse is larger in Word than in Writer. When converting, Writer takes this into account and tries to maintain the same aspect by changing the size of the application dependent-margins.
However, this computation is defeated if you space vertically your text with empty paragraphs (and other manual formatting). Doing so does not relate your paragraphs to the page break events generated during text lay out. An empty paragraph can be shifted to the start of a page and due to the difference in handling white space at head of page between both applications, you quickly accumulate an appreciable difference.
As already mentioned, save in native .odt format for your own use. If you are constrained to export .doc(x), mitigate the differences by formatting with styles, at least paragraph styles because they also exist in Word. Their effect is fully predictable.
Avoid absolutely round trips between both formats because the successive conversion damage the internal formatting dictionary by overloading it with intermediate one-shot conversion items which are no longer used and never erased.
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