Yes that is a possibility, if you want to know for sure whether there is actual two-way communication enable "Accounting" on the relevant rule. Every 10 minutes (if the connection lasts that long) or when the connection ends, extra information will be added to the original Accept log such as connection time, payload bytes sent and received, and the egress interface on the firewall for the accepted connection (useful for finding a firewall routing table issue). Assuming you get nonzero connect time and payload bytes values, two way communication is working. If those particular counters are all zero, connectivity is not working.
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