questionable editorial practices

Hello AskAcademia,

TL;DR: I am suspicious regarding an article that was accepted as I was a reviewer, should I just let it go ? lack of transparency in the reviewing process; conflict of interest involved

I was recently invited to review a manuscript submitted to a journal associated with a professional association. In the manuscript, the authors test the effects of a behavioral intervention (with commercial puproses/conflict of interests). The intervention is based on a method in which I have expertise and that is rarely used in this specific subfield.

The manuscript was honestly terrible, with several biases at different steps of the research, inappropriate statistics, and the (very positive) conclusions were barely supported by the data.

First reviewing phase:

I recommended rejection, explianing my broad concerns (which were sufficient to point out the flaws of the article for the editor to take their decision). Another reviewer accepted the manuscript without modifications and just asked one or two questions out of curiosity. The editor requested major revisions, based partly on my comments. The authors responded to my broad remarks but unfortunately the manuscript was still not suitable for publication

Second review phase:

I hesitated to withdraw from the review process but felt that I needed to be constructive and explain why the manuscript was still not sufficient and how the limitations of the methods could be avoided by future studies. I provided a more detailed review in order to point out the numerous problems point by point. My report was structured by 1) thanking the authors for modifications, 2) stating that I suggest rejection because of 3 major reasons that were briefly detailed (important for the conclusions of my story), and 3) detailing all the remarks that I had about the manuscript in what I hope was some constructive feedback.

I really wanted to be as constructive and neutral as possible, without hurting the authors' feelings. The other reviewer accepted without modifications once more. The editor asked the authors to do major revisions by integrating my comments point by point and adding a limitations section (which, in my opinion, was a fair compromise between both reviews).

Conclusion :

One month later, I receive a notification from editorial manager:

• the article has been accepted
• the responses to reviewer's comments have not been uploaded on EM, nor the modified manuscript
• I had to ask the journal manager to send me the responses to reviewer and manuscript. I was sent one small document responding to the three major reasons that introduced my long review (less than 10% of my comments). I had to send an other email again for the manuscript with visible modifications and one sentence and some p values were modified after my comments.

I am concerned because I feel like the process is not very transparent. I am even more concerned in relation to the conflicts of interests

Also, the article was accepted after the authors responded to a small part of my comments, and even if they did not need to do everything as I said, I feel like a broad response to the other remarks would have been appropriate for the editor to evaluate the changes.

What would you do ? Should I just let it go ?