What's breaking my task dependencies when using elapsed day duration

Question

Hi

I ran into an issue today where my smartsheet timeline was updated without any user's input and several dates were changed cascading to the entire timeline. I tracked it down to several tasks and started correcting them, realising that there is some issue when dependencies are using regular "day" duration and some are using "elapsed time" or "e-day" duration. I illustrated it below

On the left is timeline from today. on the right is a snapshot from yesterday. Planned start is determined by Predecessors. Planned Finish is determined by Planned Start+Duration. Desired Finish Date is a static number entered manually for reference.

Line 424 has changed today (without user input) and I manually updated the predecessor from 927FS+48d to 927FS+8d which mostly restored correct dates after i also fixed the pre-requisite 927.

It's the same issue for 919 which is the first in series of pre-requisites for 927. I had to change 891FS-14d to 891-5d to restore correct date for task 919.

891 has the correct dates both today and yesterday, no changes.

I then spotted the same problem for separate series of tasks which  i haven't updated yet.

Line 1002 is the same today as it was yesterday and it is a pre-requsite for 1117.

Nobody changed anything about line 1117, yet today the date changed from august (correct) to nov/dec (incorrect). I actually can't update it to start on correct date (23 Aug) because it's a sunday and by changing predecessor lag I can only set it to 21st or 24th (Fri/Mon), even though yesterday it was possible to set to 23rd (sun, correct start date)

I suspect that the issue is caused by using regular day duration for pre-requisite (e.g. 1002) and elapsed time days duration for dependent task (e.g. 1117) but i cannot explain what is the exact issue and why everything suddenly changed this morning without anyone's input. The sheet uses Mon-Fri as working days and 8h as length of day

Was there some Smartsheet update today which changed how these durations interact? Is there an inherent issue when task using elapsed time duration has a pre-requisite with regular day duration?

Georgie · Answer

Hi @JK1111,

As the dates don’t seem to have been calculated in your sheet correctly according to how your predecessors are set up, I recommend reaching out to our support team for them to investigate this issue.

Thanks,

Georgie

JK1111 · Answer

Thanks for sharing, I think I ran across the issue you mentioned but it is separate from the current problem. Maybe i can illustrate it with line 1117, where beforehand the dates were 23Aug-28Aug but now, without any user change we can find in the logs, the dates changed to Nov 30-Dec 5 even though the driving predecessor dates are the same. the only explanation i can think of is how the lag is calculated but i do not understand why it would change when nothing was changed in the sheet.

LaurieneE · Answer

I believe you have just noticed an issue that has been there since Elapsed time was introduced, where it is off by one day when preceding the duration with e.