The same error I am getting only in admin mode, not in edit+ , as you said all the changes saved even if the error is there
Fatal error: Uncaught exception 'Exception' with message: 'Data supplied for unserialization was not a string' in [SYSTEM_ROOT]/packages/mirror/vendor/lyte/serial/src/Unserializer.php(19): Lyte\Serial\Unserializer->__construct(Array)
#1 [SYSTEM_ROOT]/vendor/lyte/serial/src/Serial.php(10): Lyte\Serial\Serial::unserialize(Array)
#2 [SYSTEM_ROOT]/core/include/asset_attribute.inc(526): Lyte\Serial\Serial::isSerialized(Array)
#3 [SYSTEM_ROOT]/core/include/asset_attribute.inc(516): Asset_Attribute->unserialiseValue(Array)
#4 [SYSTEM_ROOT]/core/include/asset.inc(5001): Asset_Attribute->processedKeywordValue()
#5 [SYSTEM_ROOT]/core/assets/files/image/image.inc(1105): Asset->_getKeywordReplacement('asset_data')
#6 [SYSTEM_ROOT]/core/include/asset.inc(4355): Image->_getKeywordReplacement('asset_data')
#7 [SYSTEM_ROOT]/fudge/general/text.inc(2071): Asset->getKeywordReplacement('asset_data')
#8 [SYSTEM_ROOT]/fudge/general/text.inc(543): _evalute_as_asset_modifier(Array, Array)
#9 [SYSTEM_ROOT]/fudge/general/text.inc(360): apply_keyword_modifier(Array, Array, Array, '')
#10 [SYSTEM_ROOT]/core/include/asset_edit_interface.inc(1960): apply_keyword_modifiers(Array, Array, Array)
#11 [SYSTEM_ROOT]/core/assets/bodycopy/bodycopy_containers/bodycopy_div/bodycopy_div_edit_fns.inc(835): Asset_Edit_Interface->getKeywordsReplacementsForPaint(Object(Bodycopy_Div #810005), Object(Backend_Outputter), Object(Layout #809972), Array, true, false, '')
#12 [SYSTEM_ROOT]/core/assets/bodycopy/bodycopy_containers/bodycopy_div/bodycopy_div_edit_fns.inc(460): Bodycopy_Div_Edit_Fns->paintCustomLayoutInterface(Object(Bodycopy_Div #810005), '809971...', true)
#13 [SYSTEM_ROOT]/core/assets/bodycopy/bodycopy/bodycopy_edit_fns.inc(265): Bodycopy_Div_Edit_Fns->paintContainer(Object(Bodycopy_Div #810005), Object(Backend_Outputter), 'bodycopy_810002', false, Object(Bodycopy #810002))
#14 [SYSTEM_ROOT]/core/include/asset_edit_interface.inc(1559): Bodycopy_Edit_Fns->paintBodycopy(Object(Bodycopy #810002), Object(Backend_Outputter), 'bodycopy_810002') via call_user_func_array()
#15 [SYSTEM_ROOT]/core/include/asset_edit_interface.inc(1414): Asset_Edit_Interface->_doPaintFunctionCall(Object(Bodycopy #810002), Object(Backend_Outputter), 'bodycopy_810002', Object(SimpleXMLElement))
#16 [SYSTEM_ROOT]/core/include/asset_edit_interface.inc(1030): Asset_Edit_Interface->printEditInterface('screen_contents', Object(Bodycopy #810002), Object(Backend_Outputter), false, Array, '')
#17 [SYSTEM_ROOT]/core/include/asset.inc(6435): Asset_Edit_Interface->paint(Object(Bodycopy #810002), Object(Backend_Outputter), false)
#18 [SYSTEM_ROOT]/core/assets/bodycopy/bodycopy/bodycopy.inc(309): Asset->paintBackend(Object(Backend_Outputter))
#19 [SYSTEM_ROOT]/core/include/asset_manager_edit_fns.inc(255): Bodycopy->paintBackend(Object(Backend_Outputter))
#20 [SYSTEM_ROOT]/core/include/asset_manager.inc(9967): Asset_Manager_Edit_Fns->paintBackend()
#21 [SYSTEM_ROOT]/core/include/backend.inc(1244): Asset_Manager->paintBackend(Object(Backend))
#22 [SYSTEM_ROOT]/core/include/backend.inc(372): Backend->_printMain()
#23 [SYSTEM_ROOT]/core/include/backend.inc(313): Backend->paintOutputter(Object(Backend_Outputter), 'main')
#24 [SYSTEM_ROOT]/core/include/mysource.inc(6247): Backend->paint()
#25 [SYSTEM_ROOT]/core/include/mysource.inc(638): MySource->printBackend()
#26 [SYSTEM_ROOT]/core/web/index.php(28): MySource->start()