1x ...lvUI_Enhanced\modules\unitframes\update_elements.lua:34: attempt to call upvalue 'GetPlayerMapPosition' (a nil value)
...lvUI_Enhanced\modules\unitframes\update_elements.lua:34: in function `?'
ElvUI\Libraries\AceTimer-3.0\AceTimer-3.0-17.lua:55: in function <ElvUI\Libraries\AceTimer-3.0\AceTimer-3.0.lua:50>

Locals:
self =

{
Update_AssistHeader = defined @ElvUI\Modules\unitframes\groups\assist.lua:55
modules = {
}
CancelTimer = defined @ElvUI\Libraries\AceTimer-3.0\AceTimer-3.0.lua:147
RaidRoleUpdate = defined @ElvUI\Modules\unitframes\elements\raidroleicons.lua:48
Construct_PowerBar = defined @ElvUI\Modules\unitframes\elements\power.lua:14
arena1 = ElvUF_Arena1 {
}
Construct_Buffs = defined @ElvUI\Modules\unitframes\elements\auras.lua:27
Construct_ArenaFrames = defined @ElvUI\Modules\unitframes\groups\arena.lua:53
Configure_RaidDebuffs = defined @ElvUI\Modules\unitframes\elements\raiddebuffs.lua:33
UpdateHealComm = defined @ElvUI\Modules\unitframes\elements\healprediction.lua:117
UpdatePrep = defined @ElvUI\Modules\unitframes\groups\arena.lua:26
ADDON_LOADED = defined @ElvUI\Modules\unitframes\unitframes.lua:1126
FrameGlow_CheckMouseover = defined @ElvUI\Modules\unitframes\elements\frameglow.lua:294
ApplyUnitFrameEnhancements = defined @ElvUI_Enhanced\modules\unitframes\construct_elements.lua:145
db = {
}
Update_TankFrames = defined @ElvUI\Modules\unitframes\groups\tank.lua:86
SetEnabledState = defined @ElvUI\Libraries\AceAddon-3.0\AceAddon-3.0.lua:455
Hook = defined @ElvUI\Libraries\AceHook-3.0\AceHook-3.0.lua:274
instanceMapIDs = {
}
Construct_TargetTargetFrame = defined @ElvUI\Modules\unitframes\units\targettarget.lua:12
Raid40SmartVisibility = defined @ElvUI\Modules\unitframes\groups\raid40.lua:65
UpdateFillBar = defined @ElvUI\Modules\unitframes\elements\healprediction.lua:81
FrameGlow_SetGlowColor = defined @ElvUI\Modules\unitframes\elements\frameglow.lua:184
Construct_BossFrames = defined @ElvUI\Modules\unitframes\groups\boss.lua:18
UnregisterAllEvents = defined @ElvUI\Libraries\CallbackHandler-1.0\CallbackHandler-1.0.lua:200
Construct_RaidDebuffs = defined @ElvUI\Modules\unitframes\elements\raiddebuffs.lua:10
assist = ElvUF_Assist {
}
Update_ArenaFrames = defined @ElvUI\Modules\unitframes\groups\arena.lua:122
Construct_RaidpetFrames = defined @ElvUI\Modules\unitframes\groups\raidPets.lua:19
groupPrototype = {
}
Construct_InfoPanel = defined @ElvUI\Modules\unitframes\elements\infopanel.lua:7
Configure_HealthBar = defined @ElvUI\Modules\unitframes\elements\health.lua:52
GetName = defined @ElvUI\Libraries\AceAddon-3.0\AceAddon-3.0.lua:310
classMaxResourceBar = {
}
name = "ElvUI_UnitFrames"
Construct_Range = defined @ElvUI\Modules\unitframes\elements\range.lua:20
Disable = defined @ElvUI\Libraries\AceAddon-3.0\AceAddon-3.0.lua:345
Construct_FocusFrame = defined @ElvUI\Modules\unitframes\units\focus.lua:15
FrameGlow_ElementHook = defined @ElvUI\Modules\unitframes\elements\frameglow.lua:31
AuraIconUpdate = defined @ElvUI\Modules\unitframes\elements\auras.lua:362
PostCastStop = defined @ElvUI\Modules\unitframes\elements\castbar.lua:428
Unhook = defined @ElvUI\Libraries\AceHook-3.0\AceHook-3.0.lua:418
ClearChildPoints = defined @ElvUI\Modules\unitframes\unitframes.lua:345
Configure_ReadyCheckIcon = defined @ElvUI\Modules\unitframes\elements\read

I'm not 100% sure if this covers everything you were doing with it, but I made a quick fix by replacing line 34 in update_elements.lua with:

Although it wasn't mentioned in the API, just using GetPlayerMapPosition(unit) doesn't function the way it used to.

Made that change for a guildy and he said it resolved the issue for him