Example https://commons.wikimedia.org/wiki/File:SVG_text_position_bug.svg
A bug is reproduced if each letter has its own coordinates.
Code sample.
lang=svg
<text
y="149.56369"
x="97.536133"
style="font-variant:normal;font-weight:normal;font-stretch:normal;font-size:2.82222199px;font-family:Helvetica;-inkscape-font-specification:Helvetica;writing-mode:lr-tb;fill:#231f20;fill-opacity:1;fill-rule:nonzero;stroke:none;stroke-width:0.35277775"
id="text11190">
<tspan
style="stroke-width:0.35277775"
x="97.536133 99.260513 99.887047 101.4562 103.02535 104.43646 105.22105 106.7902 107.57478 108.51458 109.29916 110.23895 111.80811 112.43465 113.06118"
y="149.56369"
sodipodi:role="line"
id="tspan11188">Flaps 0 (trail)</tspan>
</text>
If these coordinates are removed (in the sample it is “99.260513 99.887047 101.4562 103.02535 104.43646 105.22105 106.7902 107.57478 108.51458 109.29916 110.23895 111.80811 112.43465 113.06118"), it renders correctly.
In the preview on the upload page, this file is displayed correctly. https://commons.wikimedia.org/w/index.php?title=Special:Upload