Slideshow mailpoet:Trying to get property of non-object in slideshow.php

Hi,
I am using your slideshow plugin and the mailpoet newsletters plugin . When I add/edit form in mailpoet, or when I add theme in mailpoet I get a notice: “Trying to get property of non-object in \plugins\slideshow-jquery-image-gallery\slideshow.php and \plugins\slideshow-jquery-image-gallery\SlideshowPluginSlideInserter.php”.
Everything seems working. Should I look for a way to fix this? Should I report this to mailpoet author?
Thank you!
Plugin slideshow: https://wordpress.org/support/plugin/slideshow-jquery-image-gallery
Plugin mailpoet newsletters: http://wordpress.org/plugins/wysija-newsletters/

https://wordpress.org/plugins/slideshow-jquery-image-gallery/