Elementor give their explain well. They said, some optimization settings might cause the problem.
And the link you provide mentioned to disable some setting about optimization and cache option. After I disabled them, the problem solved. So I would say there might be some problem between elementor and Xstore’s optimization setting.
Since our hosting provider has server cache function, I think with the optimization setting disabled in Xstore, it won’t bring slow user experience to my users or take too much server calculating resource. So the solution your provided is acceptable for now.
Your reply really helps! Many thanks!
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