fix listener session exception

[kaori-seasons]

What this PR does:
Related to issue-457

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-commenter]

Codecov Report

Merging #458 (a07b14b) into develop (00d0150) will increase coverage by 0.06%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop     #458      +/-   ##
===========================================
+ Coverage    37.20%   37.26%   +0.06%     
===========================================
  Files           55       56       +1     
  Lines         3790     3805      +15     
===========================================
+ Hits          1410     1418       +8     
- Misses        2220     2224       +4     
- Partials       160      163       +3     

Impacted Files	Coverage Δ
pkg/server/cluster_manager.go	36.84% <0.00%> (-0.58%)	⬇️
pkg/cluster/loadbalancer/hash/consistent_hash.go	70.00% <0.00%> (ø)

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