Intermittent segfault in collection.exists

I ran into this while looking at another issue, twice now. I didn't explore it much yet, but here is the top of the stack trace.

System Integrity Protection: enabled

Crashed Thread: 0 Dispatch queue: com.apple.main-thread

Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY

Application Specific Information:
abort() called

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libsystem_kernel.dylib 0x00007fff71c3849a __pthread_kill + 10
1 libsystem_pthread.dylib 0x00007fff71cf56cb pthread_kill + 384
2 libsystem_c.dylib 0x00007fff71bc0a1c abort + 120
3 _libcouchbase.cpython-37m-darwin.so 0x0000000106a8a2aa pycbc_handle_assert.cold.1 + 42
4 _libcouchbase.cpython-37m-darwin.so 0x0000000106a770fd pycbc_handle_assert + 125
5 _libcouchbase.cpython-37m-darwin.so 0x0000000106a6db1f operation_completed_with_err_info + 191 (callbacks.c:144)
6 _libcouchbase.cpython-37m-darwin.so 0x0000000106a6dfe7 value_callback + 183 (callbacks.c:794)
7 libcouchbase.2.dylib 0x0000000106b26a87 rget_callback(mc_pipeline_st*, mc_packet_st*, lcb_STATUS, void const*) + 87 (get.cc:550)
8 libcouchbase.2.dylib 0x0000000106afe1e8 mcreq_dispatch_response + 11016 (handler.cc:500)
9 libcouchbase.2.dylib 0x0000000106b37c40 lcb::Server::purge_single(mc_packet_st*, lcb_STATUS) + 2512 (mcserver.cc:774)
10 libcouchbase.2.dylib 0x0000000106ac9456 mcreq_pipeline_fail + 182 (mcreq.c:916)
11 libcouchbase.2.dylib 0x0000000106b36168 lcb::Server::socket_failed(lcb_STATUS) + 56 (mcserver.cc:789)
12 libcouchbase.2.dylib 0x0000000106b3d21b timeout_handler(void*) + 59 (negotiate.cc:107)
13 libcouchbase.2.dylib 0x0000000106ad0c93 timer_callback + 595 (timer.c:45)
14 libcouchbase.2.dylib 0x0000000106ab8c7f run_loop + 719 (plugin-select.c:156)
15 libcouchbase.2.dylib 0x0000000106b4385d lcb_wait + 141 (wait.cc:110)
16 _libcouchbase.cpython-37m-darwin.so 0x0000000106a84c92 pycbc_common_vars_wait + 194 (oputil.c:739)
17 _libcouchbase.cpython-37m-darwin.so 0x0000000106a7e5a1 get_common + 1633
18 libcouchbase.cpython-37m-darwin.so 0x0000000106a7eb76 pycbc_Bucket_rgetall + 86 (get.c:580)
19 org.python.python 0x000000010595e451 _PyMethodDef_RawFastCallDict + 516