Resources randomly moving out of alignment with Activity Duration

make sure that the resouce uses the same calendar as the activity 

Thanks, I've looked at that. Some of the resources are over 300 days out!

I cant see that happening a resource starting almost a year later than the activity unless it is on a LOE 

are you looking at the early curve  ?

Is it theoretically possible that an activity with assigned resources is executed when resources are absent?

Can somebody suggest some real life example?

It wll be the "Drive activity dates" check box in the resources tab at the project window.

VERY big topic the duraton of resources vs activities in P6. Best to keep the "Drive activity dates" check box on.

It wll be the "Drive activity dates" check box in the resources tab at the project window.

VERY big topic the duraton of resources vs activities in P6. Best to keep the "Drive activity dates" check box on.

I also have the above issue in 8.3.6

I have also tried ticking the drive activity dates by default button on the Projects Resources tab.

I have a  RAG solution using 2 global changes,  but is there a more elegant solution where a single global change in the Resource assignment tab can set original duration and Remaining durations to be the same as that in the relevant activity.

The issue here is the transfer of field UDF between Activities and Resource assignments

Or any other solutions in Primavera to resolve the issue

I do not believe a Global change is a reliable substitute to good resource leveling math., otherwise there would be no need for resource leveling algorithms.  It looks like a Software Bug you will forever have to deal with until fixed.

take a look at the ones that you have to fix. See what is the same about all of these anomalies then approach it from there.

for example is it always the same resource or is the activity type a level of effort or is the activity type resource dependent ?

see if you can find a similarity among the ones that you need to change. 

Thanks Zoltan and Rafael,

Not sure what the issue or the solution is.  When I have time I might try and find out the cause.

My current solution is to

1. at activity level global change to store uncompleted tasks and LoE  OD and RD as UDF,  and in same global change reset OD and RD to 1 unit of time.

2. Open Resource assignment for activities that are not completed (ie AF="") . and fill down" OD and RD to 1 unit of time

3.  at activity level global change  restore store OD and RD from stored UDF.

It is a slow and risky process but it seems to work.  the risk is being distracted and doing global change no. 1 twice.

Are there any common fields between activities and resource assignments that I could use instead?

if its a loe then a curve has to be assigned to it or all of the budgeted units and costs will stack up on the data date.

Only one LoE.  and it seems to be ok