If you walk and drink water, you will sprint. If you drink water from a water bottle before you jump off something, your jump skill will increase. Is this a normal thing in vanilla minecraft?

Cannot reproduce.

Please force a crash by pressing F3 + C for 10 seconds while in-game and attach the crash report ([minecraft/crash-reports/crash-<DATE>-client.txt|http://hopper.minecraft.net/help/finding-minecraft-data-folder]) here.