I can't explain why the following cut 'n paste problem happens when I select some symbols within text in Firefox and then try to insert by middle-click in LibreOffice Calc.

If I select the symbols for £ (GBP), or € (Euro) and middle click upon a cell
in LOCalc, a window pops up asking "Select the Language to Use for Import". I leave it to "Automatic" which is the default setting and the symbol plus any text is pasted with the same format as the webpage. The symbols are then displayed correctly in LOCalc.

However, if I enter a cell by double clicking on it, or by clicking in the edit bar, then middle click to enter the selection, both £ and € symbols are
entered in some strange code - e.g. \u20ac

Other browsers do not exhibit this behaviour. Firefox has been installed with these flags:

Installed versions: 91.7.0(esr)(20:02:31 10/03/22)(clang dbus gmp-autoupdate openh264 system-av1 system-harfbuzz system-icu system-jpeg system-libevent system-libvpx system-webp wayland -debug -eme-free -geckodriver -hardened - hwaccel -jack -lto -pgo -pulseaudio -screencast -selinux -sndio -system-png - wifi CPU_FLAGS_ARM="-neon" L10N="en-GB -ach -af -an -ar -ast -az -be -bg -bn - br -bs -ca -ca-valencia -cak -cs -cy -da -de -dsb -el -en-CA -eo -es-AR -es-CL -es-ES -es-MX -et -eu -fa -ff -fi -fr -fy -ga -gd -gl -gn -gu -he -hi -hr -hsb -
hu -hy -ia -id -is -it -ja -ka -kab -kk -km -kn -ko -lij -lt -lv -mk -mr -ms - my -nb -ne -nl -nn -oc -pa -pl -pt-BR -pt-PT -rm -ro -ru -sco -si -sk -sl -son -sq -sr -sv -szl -ta -te -th -tl -tr -trs -uk -ur -uz -vi -xh -zh-CN -zh-TW")

and libreoffice with these:

Installed versions: 7.2.5.2^s(08:42:14 03/02/22)(-offlinehelp L10N="en en-
GB -af -am -ar -as -ast -be -bg -bn -bn-IN -bo -br -brx -bs -ca -ca-valencia - ckb -cs -cy -da -de -dgo -dsb -dz -el -en-ZA -eo -es -et -eu -fa -fi -fr -fur - fy -ga -gd -gl -gu -gug -he -hi -hr -hsb -hu -id -is -it -ja -ka -kab -kk -km -kmr-Latn -kn -ko -kok -ks -lb -lo -lt -lv -mai -mk -ml -mn -mni -mr -my -nb - ne -nl -nn -nr -nso -oc -om -or -pa -pl -pt -pt-BR -ro -ru -rw -sa -sat -sd - si -sid -sk -sl -sq -sr -sr-Latn -ss -st -sv -sw-TZ -szl -ta -te -tg -th -tn - tr -ts -tt -ug -uk -uz -ve -vec -vi -xh -zh-CN -zh-TW -zu")

Any idea why this is happening and how I could fix it?
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