Fix an assertion failure which happens when a DTLS 1.3 client receive… #297

Job	Run time
basic_clang	7m 34s
basic_gcc	7m 33s
check_docs	58s
check_update	1m 13s
check-ansi	2m 37s
minimal	2m 33s
no-deprecated	5m 37s
non-caching	17m 28s
no-shared-macos (macos-13)	7m 58s
no-shared-ubuntu	5m 24s
no-shared-macos (macos-14)	5m 9s
self-hosted	0s
address_ub_sanitizer	10m 46s
enable_non-default_options	5m 12s
full_featured	7m 18s
fuzz_tests	2m 56s
memory_sanitizer	19m 21s
threads_sanitizer	5m 44s
external-test-cf-quiche	3m 54s
external-test-pyca (1.51.0, 3.9)	6m 19s
external-tests	11m 54s
legacy	4m 41s
no-legacy	5m 59s
out-of-readonly-source-and-install-macos (macos-13)	12m 41s
out-of-readonly-source-and-install-macos (macos-14)	7m 50s
out-of-readonly-source-and-install-ubuntu	8m 33s
	2h 57m 12s

Provide feedback