Multi EXR layers disappearing on heavy comp

I am trying to composite a 2K shot off a multilayer exr out of blender 2.69.
My major problem is that for no reason at all, the INPUT IMAGE layer node meanu seems to get confused as to what layer it is meant to be using during the comp. Worse still is when I open project, the nodes have swapped around the layers that they are meant to be looking at. I have the same problem on 2.69 & 2.7. Also, opening the exrs takes ages which is not the case on the same machine in Nuke.
Has anyone else seen this ? Is there a solution?

Shot in the dark: have you changed these files since they were first loaded? Particularly adding or removing passes/layers?

No. Strange things really.
I have not found out why but I have found a very useful addon now available in 2.7 that refreshes at a click of a button.
http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Nodes/Nodes_Efficiency_Tools

Thanks for the reply

Okay, chlowden007, please fill us in – is there resolution​ of this issue, and if so, what was it?

No. I have no firm resolution to the issue. What I can confirm is that the EXR MULTI LAYER files that i am working with are large and that sometimes, after a long wait, the connection is re established. So it maybe that the real issue is how Blender opens exr files. As I mentioned above, opening EXRs in Blender is really slow in comparison to Nuke. Moving around the timeline can take minutes when the EXR are above 100MBs. The same file in Nuke on the same machine takes seconds.
And whilst I am at it, I am looking for a button that will deactivate the auto render of the comp. I can be fiddling with nodes without a viewer activateed and all of a sudden Blender starts rendering, making fast adjustment … not very fast.

Both of these issues need to be opened as high-priority bug reports to the Blender team, then . . .

I don’t know if it is really a bug. I am not a blender specilaist. On the other hand, what really would be great is that there is an option to choose the bit depth for the EXR MULTILAYER files as there is on the single layer exrs. 32bit is great … but not all the time. When you have shots that are 500 frames, as I do at the moment, 32bit file size counts for alot when opening.