Admin error on line 257 in posts-grid.php

About a week or so ago, this error began occurring any time an “Edit with Elementor” was launched. I am guessing that the error occurred with the update to WP 4.9, but I cannot be certain. Here’s what’s displayed:

“Notice: Trying to get property of non-object in /home/accountname/public_html/wp/wp-content/plugins/elementor-addon-widgets/widgets/elementor/posts-grid.php on line 257” (Repeated 4 times)

Deactivating the “Elementor Addons & Widgets” plugin results in the errors going away. I do not see any errors on the frontend, thankfully.

So I took a look at the reported line number in posts-grid.php:

256 foreach ( $terms as $term ) {
257 $options[ $term->slug ] = $term->name;
258 }

It’s not meaningful to me, but maybe someone can assist.