How to fix "Element is not reachable by keyboard" with Selenium and Handsontable?

I am currently using Handsontable as a table framework and using Selenium in Java to automate tests. This specific test which is giving me a problem sends keys to an input which is part of a <table>:

WebElement cell = fixErrorsTable.getColumnByIndex(6).get(i); // i is the current row index
cell.click();
cell.sendKeys(newValues.get(i));

I have confirmed that the fixErrorsTable, which is a Selenium Table object, has been found correctly using the CSS selector .ht_master table. However, the sendKeys method throws an error, with the specific exception being an ElementNotInteractableException:

Element <td class="current highlight"> is not reachable by keyboard

Before, when I was using Firefox v52 for Selenium tests, everything worked fine. Since I upgraded to v79, the test breaks with this error.

Things I have already tried that have failed:

1. Trying to find an <input> inside of the cell (does not exist).
2. Trying to find a <textarea> inside of the cell (does not exist).

What is the solution to this?