"Not so real" Work experience - Will this unusual experience bother me in the future?

Humble beginnings in career and being overly noble haunt me. I worked in a startup in Chennai for 3 years. But was only paid for a year. I had joined it as my parents said, 'Jobs are hard to get. Join, work, even if for free. Learn as much as you can.' I had joined to gain experience. The startup was so early stage that they didn't have any revenue for the first year and I was basically working for free. They did pay me some months in cash. For the second year, they started paying me 5k more than my expected salary. So I was happy.
But for the 3rd year, COVID hit and business was down. They said they couldn't pay anymore, but I kept working as I wasn't getting any other opportunities. I was basically working 'as and when required' and was involved for most of the days. The owner was paying me cash for 4-5 months.

When I found a new job, the owner wrote an experience letter covering all 3 years, appreciating my presence over the years. He said that a gap might create a negative image on my profile and even though you weren't being paid, you have worked as much as you can.

To sum up, there was no 'formal' joining or leaving procedure on paper. So my letter claims I have worked for 3 years and my bank statement says I haven't. I have switched 4 jobs after that and have been working in a chemical MNC in Karnataka. Luckily, the companies being small, didn't go deep into background checks so far. But can it happen in the future?

How do I resolve this? It seems like a fake experience, but it's not. What do I need to do to resolve this?
Will this unusual experience bother me in the future?

Your story looks credible. You have the certificate of the owner. Also, keep your correspondence with the earlier company as proof. If your performance is OK, they may not dig into the past.

But all this depends on the company policy in this regard. You said it is a small-scale MNC. Perhaps you don't have to worry much on this score

According to me, as long as your confessions are genuine, you don't need to really worry. Because, you don't need to remember anything and you will be telling nothing but the truth. Moreover, you have a work experience certificate from the Owner, who has been so considerate in giving you a certificate for 3 year period. If required, you can give the contact number of the Owner, so that your future employer does not get any suspicion and can always verify the veracity of your statement.

Having said that ,4 job changes in a span of 4 years (2020 to 2024) appears to be too frequent, which could certainly impact your future career, as employers will consider you as a job hopper due to the frequent job changes.

Regards

MVK

In the circumstances explained I may suggest this -
It always pays when one can be genuine and honest. Keep a brief paragraph in your profile of your previous experience and make it a point to mention the name, address & contact No.of the owner who have issued the certificate and other business contacts existed during that period as references. Don't forget to highlight the fact that you 'worked free' during the Covid lockdown & cash payments received. I'm sure any logically thinking recruiter/HR will weigh the facts & circumstances as it deserved.
There is no alternative to sincerity and total involvement in performing your duties, may be with better innovations too.
Don't be afraid. All the very best for bright career.