Can retrieve values manually set in redis-cli but unable to set new keys through Redis Reactive in Spring Boot

I'm using Spring Webflux + Reactive Redis, my goal is to use Redis as a file cache.

I was trying to set a key with a ~100MB ByteBuffer at first, didn't work. I double-checked with the debugger to make sure the file was actually being read into memory, and surely it was. I thought "maybe Redis doesn't like "big" Strings?" so I tried with the code below, still no dice. Thought maybe it could be an ACL related issue, but I checked and the default user has access to everything. "Maybe Spring can't access Redis?" nope, I checked the MONITOR output in redis-cli and the GET command is being received just fine, no signs of the SET command though. Any suggestions?

Here's my controller:

@RequestMapping(value = "/prime", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)@ResponseBodypublic Mono<String> prime() {    reactiveStringCommands.set(ByteBuffer.wrap("testkey2".getBytes()), ByteBuffer.wrap("test".getBytes()));    return reactiveStringCommands.get(ByteBuffer.wrap("testkey".getBytes())).map(bb -> new String(bb.array()));}

Relevant settings in application.properties:

spring.redis.host=localhostspring.redis.password=<password>spring.redis.port=6379

redis-cli output (testkey was manually set in the CLI, no signs of testkey2):

127.0.0.1:6379> keys *1) "testkey"127.0.0.1:6379> ACL list1) "user default on #<password> ~* +@all"127.0.0.1:6379> monitorOK1610406175.250768 [0 172.17.0.1:39104] "GET" "testkey"