Typing lag when there are too many words on a table

[Goghard]

An organization submitted me a .docx file that I have to fill. All the text in that file is inside a table with few cells (I suggested the organization to use borders instead, but they said that for now I have to use the document as they made it.) After typing a while inside the table, I noticed a lag (characters appear on the screen one or two seconds after I type them).
I restarted TextMaker, restarted the computer, and even reinstalled SoftMaker. The problem persisted. I thought it was the file, but I could reproduce the problem in a blank document: I created the document, inserted a table with a single cell, wrote enough random text in it, and when I type, there is the lag. In my system, the lag starts when the cell has around 1500 words.
This is my system info:
Operating System: Linux Mint 20.2 Cinnamon
Processor: Intel© Core™ i5-6200U CPU @ 2.30GHz × 2
Memory: 11.6 GiB
Hard Drives: 614.2 GB
Graphics Card: Intel Corporation Skylake GT2 [HD Graphics 520]

[SuperTech]

Thanks for reporting this problem. I was able to reproduce it and forwarded the details to our developer team.

[SuperTech]

I suggested the organization to use borders instead, but they said that for now I have to use the document as they made it.

Yes, you are absolutely correct, as tables are not designed for 3 pages of text in a single cell and for such work one should use borders.