Warning: Illegal offset type

Trying get a title of another post in elemenetor, object title shown, but also makes this error:

Warning: Illegal offset type in /data/f/b/fbe2cc83-b3da-42d8-9501-f27209d4d9c1/technikaizs.cz/web/wp-content/plugins/elementor/core/kits/manager.php on line 212

Warning: Illegal offset type in /data/f/b/fbe2cc83-b3da-42d8-9501-f27209d4d9c1/technikaizs.cz/web/wp-content/plugins/elementor/core/kits/manager.php on line 212

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