• Windows 10 Enterprise
• Illustrator 25.4 and later, 26, 27 (all)

When I export SVG (Save as -> Save as SVG), the path with a a fill gradient color generated a dirty long CSS code:

<?xml version="1.0" encoding="utf-8"?>
<!-- Generator: Adobe Illustrator 26.5.0, SVG Export Plug-In . SVG Version: <?xml version="1.0" encoding="utf-8"?>
<!-- Generator: Adobe Illustrator 26.5.0, SVG Export Plug-In . SVG Version: 6.00 Build 0) -->
<svg version="1.1" id="Livello_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
viewBox="0 0 50 50" style="enable-background:new 0 0 50 50;" xml:space="preserve">
<style type="text/css">
.st0{fill:url(#Element200000012443458042858059010000003463708424840614056);}
.st1{fill:url(#Element100000127017412019725090950000006481867756431396536);}
</style>
<linearGradient id="Element2_00000010313092043105879430000008226129921869105801_" gradientUnits="userSpaceOnUse" x1="0" y1="20.15" x2="50" y2="20.15">
<stop offset="0" style="stop-color:#FFFFFF"/>
<stop offset="0.3198" style="stop-color:#B738B6"/>
<stop offset="1" style="stop-color:#000000"/>
</linearGradient>
<path id="Element2" style="fill:url(#Element2_00000010313092043105879430000008226129921869105801_);" d="M27.1,22.7
c1.2,1.2,1.3,3.1,0.3,4.3c-1.2,1.2-3.1,1.3-4.3,0.3c-1.2-1.2-1.3-3.1-0.3-4.3c0.6-0.7,1.5-1,2.3-1C25.7,22,26.4,22.2,27.1,22.7z
M50,25c0,1.6-0.1,3.1-0.4,4.6c-0.1,0-0.2-0.1-0.3-0.1h-8.6c-0.6,0-1.1,0.4-1.3,0.9c-2.3,5.9-8.1,9.9-14.4,9.9s-11.9-3.8-14.3-9.6
c-0.2-0.5-0.7-0.8-1.3-0.8H0.8c-0.1,0-0.2,0.1-0.3,0.1C0.2,28.4,0,26.7,0,25C0,11.2,11.1,0,25,0C38.8,0,50,11.2,50,25z M25.1,9.5
c2.4,0,4.8,0.6,7,1.7c0.4,0.2,0.9,0,1.2-0.4c0.2-0.4,0-0.9-0.4-1.2c-2.5-1.3-5.1-1.9-7.9-1.9c-9.5,0-17.2,7.8-17.2,17.2
c0,0.5,0.4,0.9,0.9,0.9s0.9-0.4,0.9-0.9C9.6,16.4,16.5,9.5,25.1,9.5z M29,22.8L38.2,12c0.5-0.6,0.5-1.4-0.1-1.9
c-0.6-0.5-1.4-0.4-1.9,0.2l-9.1,10.6C25.3,20,23,20.4,21.6,22c-1.7,2-1.4,4.9,0.5,6.5c0.9,0.7,1.9,1.1,3,1.1c1.2,0,2.5-0.6,3.4-1.6
C29.7,26.5,29.9,24.4,29,22.8z M42.3,25c0-3.7-1.1-7.2-3.2-10.1c-0.3-0.4-0.9-0.5-1.3-0.2c-0.4,0.3-0.5,0.9-0.2,1.3
c1.9,2.6,2.9,5.8,2.9,9c0,0.5,0.4,0.9,0.9,0.9S42.3,25.5,42.3,25z"/>
<linearGradient id="Element1_00000036958541660793620670000017130290864928659633_" gradientUnits="userSpaceOnUse" x1="1.25" y1="41.15" x2="48.95" y2="41.15">
<stop offset="0" style="stop-color:#FFFFFF"/>
<stop offset="0.3198" style="stop-color:#B738B6"/>
<stop offset="1" style="stop-color:#000000"/>
</linearGradient>
<path id="Element1" style="fill:url(#Element1_00000036958541660793620670000017130290864928659633_);" d="M25.1,43.2
c-7.1,0-13.5-4.1-16.4-10.5H1.2C4.5,42.8,14,50,25,50c11.3,0,20.8-7.4,23.9-17.7l-7.2,0.1C38.8,38.9,32.2,43.2,25.1,43.2z"/>
</svg>

The problem exists from 25.4.1 version