For the two days that your plugin was installed I received messages from WordFence. These are the files that were changed:
Alert generated at Thursday 11th of December 2014 at 01:50:37 AM
Warnings:
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/9c/3c/1820db174d7efba416743bbb9bf744e8454155f8129f69296092b49c45d3.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/aa/61/6d3f918f480e4f6f0dabdeee1324d87d759ec18352a21a1cfcee8802f528.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/dc/78/b950182efb8f436b144938fb0dc48cf395d7daabe20293234dbcf2b26545.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/e2/c5/4407992fc7f64fc763c8fa820f4d1ef92de870acc466bbd2209e5965d014.php
Alert generated at Wednesday 10th of December 2014 at 07:43:19 AM
Warnings:
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/08/e4/4d5fc50332367b2d7e81902230ac0e7ea950ee003ec7a490752fc6534c00.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/1f/25/bacc16e82305cef35f2d4954e3a58cf88f86b74ba3bdfdb3edd107c03a6d.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/21/cf/b7e0c7543e64053052e7d3df401f7fdde0a3873bf1f837c0be10edd95099.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/27/15/acf678c380d630c83d3a7e40c2555c0b4cb21a16d95a1cc06a601f043e45.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/49/32/ea4178e92f66ddbdb1feb9ec1496773dcb031265fc870a3e981abc68ca2a.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/5c/a1/499a9c32090a9a368a28b4c13261022bf5d11f22b5211fb873b104fc70e4.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/c1/80/4f545c5b33b8114cc21fe6cb5c59952fa8c7d680d237c3ca4d3f63b96c1c.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/f9/27/e9ebb965697e227fa8ba7991946a80bc34917fe8e437edbc0c4567956326.php
* Modified plugin file: wp-content/plugins/all-in-one-event-calendar/cache/twig/fe/5f/a372e0eb51f713beb664be0cf0c9c8c78572b1851c15eac685f6cd98c181.php
Unfortunately I didn’t save these files so I don’t know what the changes were as I lost patience and uninstalled the plugin. Still seems odd that they were changed if they are only templates.