error in rendering text/tspan element

[Lode Leroy]

I was typing in svg manually, and open the file in inkscape.
I tried to render "Postno" with the last o raised and underlined, as follows

<text x="10" y="130" class="text">Postn<tspan dy="-5" class="sup">o</tspan>:</text>

according to the svg documentation, the "dy=-5" should only apply inside the "tspan" element,
but the following element is also affected.

I managed to workaround as follows:

<text x="10" y="130" class="text">Postn<tspan dy="-5" class="sup">o</tspan><tspan dy="+5" class="text">:</tspan></text>

that's with inkscape 0.92 both on windows and on linux

[Lode Leroy (lode-leroy)]

seems like I misread the documentation...