Call to a member function path() on null errors on Grav 1.7

[thekenshow]

The table-importer plugin v2.2.1 works fine on Grav 1.6.16 but after upgrading to 1.7.x, it throws a Call to a member function path() on null error at user/plugins/table-importer/TableImporterShortcode.php:166.

The error does not occur if the individual page cache is disabled ( cache_enable: false ). The relevant page config is as follows:

title: 'My Tableimporter Page'
tablesorter:
    active: true
    raw: true
    tablenums: '1,2'
    include_widgets: true
    include_metadata: true
    themes: bootstrap
    args:
        1:
            theme: bootstrap
            widgets:
                - filter
                - zebra
        2:
            theme: bootstrap
            widgets:
                - filter
                - zebra
---