1 – I disabled all others plugins also I’m not using any cache plugin, didn’t seems to work also, any widget from xStore seems to behave like ajaxfied.
2 – I’m using Loco Translate, I tried to find this “proceed to checkout” string manualy but didn’t found it. Neither on Xstore theme/child/xstore core. Just needed to “sync” to find some strings that needs translation.
Could you take a look?