Steps to reproduce the issue

Deployed a new version and a new updateserver.xml on Update site

Expected result

Joomla updater should indicate update of new version (installed "1.2.0.1" , new "1.2.0.2")

Actual result

on Joomla V4.1 update works as expected (update works successfully)
on Joomla V3.10.6 no update Info detected and indicated

System information (as much as possible)

Her my snippet of plugin xml

..
	<updateservers>
		<server type="extension" priority="1" name="tipbutton Updates">https://www.jschmidt-systemberatung.de/downloads/tipbutton_updates.xml</server>
	</updateservers>
..

and
update server xml:

<?xml version="1.0" encoding="iso-8859-1"?>
<updates>
	<update>
		<name>Button Tooltip</name>
		<description>tipbutton editor-xtd Button plugin</description>
		<element>tipbutton</element>
		<type>plugin</type>
		<client>site</client>
		<folder>editors-xtd</folder>
		<version>1.2.0.2</version>
		<infourl title="jmootips">https://www.jschmidt-systemberatung.de/</infourl>
		<downloads>
			<downloadurl type="full" format="zip">https://www.jschmidt-systemberatung.de/downloads/plg_tipbutton-v1.2.0.zip</downloadurl>
		</downloads>
		<sha256></sha256>
		<tags>
			<tag>stable</tag>
		</tags>
		<targetplatform name="joomla" version="3.(9|10]" />
	</update>
	<update>
		<name>Button Tooltip</name>
		<description>tipbutton editor-xtd Button plugin</description>
		<element>tipbutton</element>
		<type>plugin</type>
		<client>site</client>
		<folder>editors-xtd</folder>
		<version>1.2.0.2</version>
		<infourl title="jmootips">https://www.jschmidt-systemberatung.de/</infourl>
		<downloads>
			<downloadurl type="full" format="zip">https://www.jschmidt-systemberatung.de/downloads/plg_tipbutton-v1.2.0.zip</downloadurl>
		</downloads>
		<sha256></sha256>
		<tags>
			<tag>stable</tag>
		</tags>
		<targetplatform name="joomla" version="4.(0|1)" />
	</update>
</updates>

Additional comments

Checked entries database (#__extensions, #__update_sites, #__upadte_sites_extensions) all looks OK. update_sites has correct pointer to update_sites_extensions and update_site_extension point correctly to plugin.