Array data not reactive when mutating it and not using it in template or computed

[ig1na]

Version

3.0.0

Reproduction link

SCF Playground

Steps to reproduce

Set an array as data, do not use/display it in template, push some data into it, the array is not updated.

What is expected?

The array should be updated when pushing elements into it.

What is actually happening?

The array is not updated, except if it is displayed or used in the template

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If you uncomment the part in the template on the SFC playground, the array will be updated as intended.

I wanted to check/uncheck checkboxes using a method instead of the checkboxes itself, and the checkboxes would not check/uncheck when calling the method.