Need Insights on Vacation Leave Policy

I just want to get your thoughts on something. I informed my TL about my plan to take a 5-day leave for an international trip 3 months in advance. I formally plotted the leave 1 month before the departure date, which is the allowed time based on project policy. I rarely use my leave despite traveling often, so I made sure everything was planned properly.

Here’s the issue: because many employees have resigned, the number of allotted leaves per team was reduced. As a result, my TL had to cancel 3 days of my approved leave and gave me the option to either take unpaid leave, use sick leave, or work remotely during that time. I understand the business needs, but I’m confused—is it even allowed to cancel an already approved leave because of staffing issues? I don’t have any issues with my TL since I know they’re just following the situation, but I’m starting to feel frustrated about this.

Is this something that’s typically allowed?