If I test GpgOL a bit harder with a current build of master GPGME and GpgOL I can pretty reliably get outlook to crash after decrypting a signed and ecnrypted mail fropm myself. This is not fully reproducable but by openening multiple explorers viewing the mail multiole times seesm to at least increase the chance for this crash. The last lines ion the log are pretty much unspectacular
canCertify: 1 canAuth: 0 canRenc: 0 canTimestanp: 0 isSecret: 1 isGroupOwned: 0 isQualified: 0 isDeVs: 1 isCardKey: 0 cardSerialNumber:<null>) GpgME::Subkey( fingerprint: 46ED5D7758C1BD71C27AF928FFA2FCCB2EC589F8 keyGrip: 8B8713E028E9DC05A4FEA1B70A21B293C2081819 creationTime: 1678274145 expirationTime:0 isRevoked: 0 isExpired: 0 isInvalid: 0 isDisabled: 0 canSign: 0 canEncrypt: 1 canCertify: 0 canAuth: 0 canRenc: 0 canTimestanp: 0 isSecret: 1 isGroupOwned: 0 isQualified: 0 isDeVs: 1 isCardKey: 0 cardSerialNumber:<null>) revocationKeys: ) 11:25:42/5864/windowmessages.cpp:do_in_ui_thread: Sending message of type 1102 11:25:42/9248/keycache.cpp:do_update updating: "F8D51DE0EE16E9B57009B8DE458612006D8E6F0D" with protocol OpenPGP 11:25:42/8552/windowmessages.cpp:gpgol_window_proc: Recieved user msg: 1102 11:25:42/8552/DBG_OOM/Mail 233b0fd0 Parsing done for parser num 2: 28125a80 11:25:42/8552/keycache.cpp:getFromMap using "F8D51DE0EE16E9B57009B8DE458612006D8E6F0D" for "F8D51DE0EE16E9B57009B8DE458612006D8E6F0D" 11:25:42/8552/keycache.cpp:getByFpr Cache hit for F8D51DE0EE16E9B57009B8DE458612006D8E6F0D. 11:25:42/8552/mail.cpp:updateSigstate: Classified sender as verified uid validity: 5 origin: 0 11:25:42/8552/DBG_OOM/oomhelp.cpp:get_oom_object: looking for 37cf2630->`Parent.Store' 11:25:42/8552/DBG_OOM/oomhelp.cpp:get_oom_object:411 AddRef on 37cf47e8 11:25:42/8552/DBG_OOM/oomhelp.cpp:get_oom_object:411 AddRef on 37cf4ed0 11:25:42/8552/DBG_OOM/oomhelp.cpp:get_oom_object: looking for 37cf4ed0->`Categories' 11:25:42/8552/DBG_OOM/oomhelp.cpp:get_oom_object:411 AddRef on 37cf47e8 11:25:42/9248/keycache.cpp:insertOrUpdateInFprMap Lost secret info on update. Merging. 11:25:42/9248/keycache.cpp:do_update Update job done
Which seems okay. Since this would be how a successful decryption always ends.