I have never seen bugs like those before but my guess is that they were attracted to the moisture at the fresh leaf break. I don't think they would be the cause of the leaf drop but could be a sign that the potting mix is too damp.

How long have you had the plant and when was the last time it was repotted

It is possible that the potting mix is breaking down which reduces air flow. This makes a nice environment for bugs but chokes the roots and stresses the plant.

I've had the orchid for about 3 years and repotted it less than a year ago. Should I check the roots to see if there's any rotten roots or would this cause more stress on the plant? It still has one flower on the spike.

If you just repotted you should be OK, I wouldn't disturb it again. It looks like new roots are forming where the old leaves were which is good. The leaves look a little limp but not really that bad, maybe something slightly off with the culture. What are your light conditions, temperatures and watering habits.

Okay, I will leave it
as it is for now. Yes, there are lots of new roots if you peek through the
potting medium as well, so I believe that it has enough of them to stay
healthy.

As for the conditions,
I water not more often than every ten days since the pot is quite big, it sits
on a table next to a south facing window with plenty of indirect light. The only
thing that has changed is the weather outside, which have become quite hot (around
20-25°C) during the last month. I live in Sweden and we had 10-15°C before
that. However, there is always kind of hot in our apartment (24-26°C). I use
orchid fertilizer once every month or more rarely.

And yes, the leaves are quite limp when you feel them, in contrast to what they felt like just two weeks ago.

Maybe the new potting medium has never really absorbed moisture. Some of the top roots look kind of dry to me, but I'm a newbie, so...

My phal was having a similar problem. I read on this forum to soak the entire pot for 10-15 minutes. So, once a week I set the pot in a larger container and water from the top. As the water flows through the orchid pot it fills the larger container. I let it soak a while, remove it from the larger container and let it drain in the sink before putting back in the window. It seems to be responding positively to this way of 'watering'.

I water early in the day so the excess water has time to evaporate before night time. Also, I purchase drinking water instead of using my tap water because the utility company uses chloramine as a sanitize-er.

hth :)

Ok, I will follow your advice!

Thank you so much for the help!

When I have had several leaves yellow at the same time, especially when it starts on the main stem and progresses out, there has been rot going on in the stem and I have lost the plant if there is not enough healthy stem above to send out new roots. You might peel off these yellowing leave and check undernreath.

Thank you for the advice! I ckecked the stem and there seems to be no sign of rot.