I'm writing with mistakes.(at the moment, right now) ( В этот момент)
I write with mistakes. (Как правило)

make writing mistakes
<Андриолли, "writing with mistakes" звучит как-то странно

Возможно, я ещё учусь.)

Actually, WRITING WITH MISTAKES and MAKE WRITING MISTAKES are BOTH acceptable as something a native would say, just not as often as simply “I make mistakes when I write.”

That's the good remark.)

*a good point))

Да!!!) Буду использовать a good point)

I meik mis teiks ven I rite
Mi ritin iz bed

Uly в вашем переводе тоже нету "writing with mistakes", вот и мне вариант с make (writing) mistakes показалось более приемлемым и часто употребимым

I only added two variants. I never said your variants were incorrect; on the contrary - I told you they sounded quite native. I personally don’t say WRITE WITH MISTAKES or MAKE WRITING MISTAKES, but that doesn’t mean they’re not used. I thought I made that clear.

“make mistakes when I write” gets 481,000 hits on Google: https://www.google.com/search?sxsrf=ALeKk003uWy2zynguLOjei3sPvHm57Gi2A%3A1594312715587&ei=C0gHX4y-I4yStQWN7qTgAQ&q=%22mistakes+when+I+write%22&oq=%22mistakes+when+I+write%22&gs_lcp=CgZwc3ktYWIQAzIFCCEQqwI6BAgAEB46BggAEAgQHjoFCAAQkQI6BggAEAcQHjoECAAQQzoHCAAQsQMQQzoICAAQsQMQkQI6BQgAELEDOgIIADoFCCEQoAE6CAgAEAgQBxAeUMXxCViqkApgxJEKaAJwAHgAgAGTAYgB-hSSAQQ5LjE2mAEAoAEBqgEHZ3dzLXdpeg&sclient=psy-ab&ved=0ahUKEwjM78rYzcDqAhUMSa0KHQ03CRwQ4dUDCAs&uact=5

“make writing mistakes” gets 26,000: https://www.google.com/search?sxsrf=ALeKk02WoTodkXOc40_6K78tG1xu3sWyeQ%3A1594313009304&ei=MUkHX-_pEc3EswXjgLX4Ag&q=%22make+writing+mistakes%22&oq=%22make+writing+mistakes%22&gs_lcp=CgZwc3ktYWIQAzIECAAQHjIGCAAQCBAeMgYIABAIEB4yBggAEAgQHjoECAAQRzoGCAAQBxAeOgQIIxAnOgUIABCRAjoECAAQQzoCCAA6BQgAELEDOgQIABAKOgQIABANOggIABAIEAcQHlCE2AFY0egBYOvpAWgAcAJ4AYAB2gGIAbURkgEGMTEuOS4xmAEAoAEBqgEHZ3dzLXdpeg&sclient=psy-ab&ved=0ahUKEwivxtHkzsDqAhVN4qwKHWNADS8Q4dUDCAs&uact=5

“write with mistakes” gets 55,000: https://www.google.com/search?sxsrf=ALeKk03r0Ppwxf6PaYCSGNda2zbtjJsNyw%3A1594313039948&ei=T0kHX9O6OcaEsAWlz6OABA&q=%22write+with+mistakes%22&oq=%22write+with+mistakes%22&gs_lcp=CgZwc3ktYWIQAzIECAAQHjIICAAQCBAKEB4yCAgAEAgQChAeMggIABAIEAoQHjoGCAAQCBAeOgYIABAHEB46BAgAEEM6AggAOggIABCxAxCDAToHCAAQsQMQQzoFCAAQsQM6BQgAEJECOggIABCxAxCRAjoECAAQDToICAAQCBAHEB46CggAEAgQBxAKEB5Q88ABWP_cAWCR3gFoAnAAeACAAXiIAcwSkgEEOC4xNZgBAKABAaoBB2d3cy13aXo&sclient=psy-ab&ved=0ahUKEwiTnqDzzsDqAhVGAqwKHaXnCEAQ4dUDCAs&uact=5

So I’ll repeat: MAKE WRITING MISTAKES and WRITE WITH MISTAKES are both phrases a native would say, but not as commonly as I MAKE MISTAKES WHEN I WRITE))