My immediate superior and CFO question MC given by HKL. I write up a report on them to HR after physical meeting to iron things out ..

I bluntly tell them to the face :
1. You don't play doctor role in which you are not qualified to give your opinion on my medical related matters
2. If you want to question HKL, by all means give them all call. The MC is not issued by private practitioner where there is possibility to obtain by paying .. This is government hospital
3. If you are not happy, I'm more happy to bring this to labor court. Easy win for me with all relevant submitted and filed document given to HR and my own personal record safekeeping.

From that days onwards, no one on my back including HR

You cannot penalized ppl for valid MC although you can put whatever remark to it .. I'm talking about increment, bonus and what not ..

I been in that position before; heck even get an "appreciation" award ..

Unless one have trust issue like my boss, I tell them .. call them to validate / verify if such letter or note had been issued .. simple as that if one is not disputing / disagree with the medical opinion ..