Polyline Tooltip disappears under Polygone – Leaflet

I´m struggling a bit with my tooltip for polylines.
I call them like this way:

 var Strecken = L.geoJSON(lineJson,{
        color: '#6a6a6a',
        weight: '1', 
        opacity: '1',
    }).bindTooltip(function (layer){
        return "Streckennummer: " + layer.feature.properties.STRECKE_NR + "</br>" + "Strecke: " + layer.feature.properties.STRECKE_KU + "</br>" + "Elektrfizierung: " + layer.feature.properties.ELEKTRIFIZ + "</br>" + "Gleisanzahl: " + layer.feature.properties.GLEISANZAH;
    },
    {className: 'popuptooltip'}).addTo(map);
    map.removeLayer(Strecken)

The tooltip is working fine, but only as long as my polygone layers are not chosen.
So while I have my polygones activated at the same time, the tooltip on my polylines doesn´t appear.

I tried to set them to different pane levels (polylines above polygones), but it didn´t solved the problem.
It´s kinda weird for me, because the point data aren´t affected from my polygones.

Any suggestions? Would be nice, thanks!