Report 1:
Odroid XU4 ARM PC
OS: Ubuntu 14.04 Server
Java: Open JDK7
Plugins: none

Report 2:
Raspberry Pi 2
java version "1.7.0_91"
OpenJDK Runtime Environment (IcedTea 2.6.3) (7u91-2.6.3-1~deb7u1+rpi1)
OpenJDK Zero VM (build 24.91-b01, mixed mode)

Report 3:
Raspberry Pi 2 - Raspbian GNU/Linux 8 \n \l
git-Spigot-db6de12-3f3c65f (MC: 1.8.8) (Implementing API version 1.8.8-R0.1-SNAPSHOT)
java version "1.7.0_95"
OpenJDK Runtime Environment (IcedTea 2.6.4) (7u95-2.6.4-1~deb8u1+rpi1)
OpenJDK Zero VM (build 24.95-b01, mixed mode)

Thanks for the tip. Was able to get a vanilla server running without timeout/crashes using the Oracle JDK 7. Creepers did not explode instantly on Vanilla (though all entities were very laggy).

The JDK switch also seems to have fixed the issue in Spigot. Creepers are now behaving normally. Thanks for the workaround! This definitely appears to be an issue related to OpenJDK.

I also noticed a performance improvement on server startup and around Nether portals. Previously entering a portal would often cause a client timeout, that no longer happens at least with only 1 player on.

I attempted getting a vanilla server running on my cubietruck (Linaro/Ubuntu 15.04 armhf port) using the OpenJDK 8, but it was so slow as to be unusable, it would crash on startup. I managed to get it started up with the Oracle 8 JDK arm32, but it would crash logging in while I was waiting for chunks to load. But anyway, Oracle JDK generated chunks much faster than OpenJDK, which seems to confirm what the forums say, that Orale's JVM performs much better on ARM boards.

I then tried a Spigot server using Oracle JDK, and the creepers were behaving normally. Whilst combat in general lagged more often than not, of the 6 creepers I encountered, 2 were in the distance above ground, which I approached and killed, 3 took me by surprise in the darkness of caves and blew up and the last one I heard taking drowning damage before I found him in a waterfall and killed him.

I'd recommend using the Oracle JDK, you may just be having problems with lag caused by the OpenJDK.

I have not yet been able to get the vanilla server to run on my Pi 2 without running out of memory soon after startup. I will give it another try when I have some free time and report back.

If this is something that only happens on a device we don't have that's going to be pretty difficult to fix. Especially given that means it is likely a device / java bug. What about vanilla?